En C++, la cadena és un objecte de std::string classe que representa una seqüència de caràcters. Podem realitzar moltes operacions sobre cadenes com ara concatenació, comparació, conversió, etc.
Exemple de cadena C++
Vegem un exemple senzill de cadena C++.
#include using namespace std; int main( ) { string s1 = 'Hello'; char ch[] = { 'C', '+', '+'}; string s2 = string(ch); cout<<s1<<endl; cout<<s2<<endl; } < pre> <p>Output:</p> <pre> Hello C++ </pre> <hr> <h2>C++ String Compare Example</h2> <p>Let's see the simple example of string comparison using strcmp() function.</p> <pre> #include #include using namespace std; int main () { char key[] = 'mango'; char buffer[50]; do { cout<>buffer; } while (strcmp (key,buffer) != 0); cout<<'answer is correct!!'<<endl; return 0; } < pre> <p>Output:</p> <pre> What is my favourite fruit? apple What is my favourite fruit? banana What is my favourite fruit? mango Answer is correct!! </pre> <hr> <h2>C++ String Concat Example</h2> <p>Let's see the simple example of string concatenation using strcat() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); cout << 'Enter the buffer string: '; cin.getline(buffer, 25); strcat(key, buffer); cout << 'Key = ' << key << endl; cout << 'Buffer = ' << buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let's see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;></pre></'answer></pre></s1<<endl;> Exemple de comparació de cadenes de C++
Vegem un exemple senzill de comparació de cadenes utilitzant la funció strcmp().
#include #include using namespace std; int main () { char key[] = 'mango'; char buffer[50]; do { cout<>buffer; } while (strcmp (key,buffer) != 0); cout<<\'answer is correct!!\'<<endl; return 0; } < pre> <p>Output:</p> <pre> What is my favourite fruit? apple What is my favourite fruit? banana What is my favourite fruit? mango Answer is correct!! </pre> <hr> <h2>C++ String Concat Example</h2> <p>Let's see the simple example of string concatenation using strcat() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); cout << 'Enter the buffer string: '; cin.getline(buffer, 25); strcat(key, buffer); cout << 'Key = ' << key << endl; cout << 'Buffer = ' << buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let's see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;></pre></\'answer> Exemple de concat de cadena C++
Vegem un exemple senzill de concatenació de cadenes utilitzant la funció strcat().
java afegir a una matriu
#include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); cout << 'Enter the buffer string: '; cin.getline(buffer, 25); strcat(key, buffer); cout << 'Key = ' << key << endl; cout << 'Buffer = ' << buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: Welcome to Enter the buffer string: C++ Programming. Key = Welcome to C++ Programming. Buffer = C++ Programming. </pre> <hr> <h2>C++ String Copy Example</h2> <p>Let's see the simple example of copy the string using strcpy() function.</p> <pre> #include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;></pre></endl;> Exemple de còpia de cadena C++
Vegem un exemple senzill de copiar la cadena utilitzant la funció strcpy().
#include #include using namespace std; int main() { char key[25], buffer[25]; cout << 'Enter the key string: '; cin.getline(key, 25); strcpy(buffer, key); cout << 'Key = '<< key << endl; cout << 'Buffer = '<< buffer<<endl; return 0; } < pre> <p>Output:</p> <pre> Enter the key string: C++ Tutorial Key = C++ Tutorial Buffer = C++ Tutorial </pre> <hr> <h2>C++ String Length Example</h2> <p>Let's see the simple example of finding the string length using strlen() function.</p> <pre> #include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;></pre></endl;> Exemple de longitud de cadena C++
Vegem un exemple senzill de trobar la longitud de la cadena mitjançant la funció strlen().
#include #include using namespace std; int main() { char ary[] = 'Welcome to C++ Programming'; cout << 'Length of String = ' << strlen(ary)<<endl; return 0; } < pre> <p>Output:</p> <pre> Length of String = 26 </pre> <h2>C++ String Functions</h2> <table class="table"> <tr> <th>Function</th> <th>Description</th> </tr> <tr> <td> int compare(const string& str) </td> <td>It is used to compare two string objects.</td> </tr> <tr> <td> <a href="/c-string-length">int length()</a> </td> <td>It is used to find the length of the string.</td> </tr> <tr> <td> void swap(string& str) </td> <td>It is used to swap the values of two string objects.</td> </tr> <tr> <td>string substr(int pos,int n)</td> <td>It creates a new string object of n characters.</td> </tr> <tr> <td> <a href="/c-string-size">int size()</a> </td> <td>It returns the length of the string in terms of bytes.</td> </tr> <tr> <td> void resize(int n) </td> <td>It is used to resize the length of the string up to n characters.</td> </tr> <tr> <td> <a href="/c-string-replace">string& replace(int pos,int len,string& str)</a> </td> <td>It replaces portion of the string that begins at character position pos and spans len characters.</td> </tr> <tr> <td> <a href="/c-string-append">string& append(const string& str)</a> </td> <td>It adds new characters at the end of another string object.</td> </tr> <tr> <td> char& at(int pos) </td> <td>It is used to access an individual character at specified position pos.</td> </tr> <tr> <td> <a href="/c-string-find">int find(string& str,int pos,int n)</a> </td> <td>It is used to find the string specified in the parameter.</td> </tr> <tr> <td> int find_first_of(string& str,int pos,int n) </td> <td>It is used to find the first occurrence of the specified sequence.</td> </tr> <tr> <td> int find_first_not_of(string& str,int pos,int n ) </td> <td>It is used to search the string for the first character that does not match with any of the characters specified in the string.</td> </tr> <tr> <td> int find_last_of(string& str,int pos,int n) </td> <td>It is used to search the string for the last character of specified sequence.</td> </tr> <tr> <td> int find_last_not_of(string& str,int pos) </td> <td>It searches for the last character that does not match with the specified sequence.</td> </tr> <tr> <td> string& insert() </td> <td>It inserts a new character before the character indicated by the position pos.</td> </tr> <tr> <td> int max_size() </td> <td>It finds the maximum length of the string.</td> </tr> <tr> <td> <a href="/c-string-push_back">void push_back(char ch)</a> </td> <td>It adds a new character ch at the end of the string.</td> </tr> <tr> <td> void pop_back() </td> <td>It removes a last character of the string.</td> </tr> <tr> <td> <a href="/c-string-assign">string& assign()</a> </td> <td>It assigns new value to the string.</td> </tr> <tr> <td> int copy(string& str) </td> <td>It copies the contents of string into another.</td> </tr> <tr> <td> char& back() </td> <td>It returns the reference of last character.</td> </tr> <tr> <td> Iterator begin() </td> <td>It returns the reference of first character.</td> </tr> <tr> <td> int capacity() </td> <td>It returns the allocated space for the string.</td> </tr> <tr> <td>const_iterator cbegin()</td> <td>It points to the first element of the string.</td> </tr> <tr> <td>const_iterator cend()</td> <td>It points to the last element of the string.</td> </tr> <tr> <td>void clear()</td> <td>It removes all the elements from the string.</td> </tr> <tr> <td>const_reverse_iterator crbegin()</td> <td>It points to the last character of the string.</td> </tr> <tr> <td>const_char* data()</td> <td>It copies the characters of string into an array.</td> </tr> <tr> <td>bool empty()</td> <td>It checks whether the string is empty or not.</td> </tr> <tr> <td>string& erase()</td> <td>It removes the characters as specified.</td> </tr> <tr> <td> char& front() </td> <td>It returns a reference of the first character.</td> </tr> <tr> <td> string&� operator+=() </td> <td>It appends a new character at the end of the string.</td> </tr> <tr> <td> string& operator=() </td> <td>It assigns a new value to the string.</td> </tr> <tr> <td>char operator[](pos)</td> <td>It retrieves a character at specified position pos.</td> </tr> <tr> <td> int rfind() </td> <td>It searches for the last occurrence of the string.</td> </tr> <tr> <td> iterator end() </td> <td>It references the last character of the string.</td> </tr> <tr> <td> reverse_iterator rend() </td> <td>It points to the first character of the string.</td> </tr> <tr> <td> void shrink_to_fit() </td> <td>It reduces the capacity and makes it equal to the size of the string.</td> </tr> <tr> <td> char* c_str() </td> <td>It returns pointer to an array that contains null terminated sequence of characters.</td> </tr> <tr> <td> const_reverse_iterator crend() </td> <td>It references the first character of the string.</td> </tr> <tr> <td> reverse_iterator rbegin() </td> <td>It reference the last character of the string.</td> </tr> <tr> <td>void reserve(inr len)</td> <td>It requests a change in capacity.</td> </tr> <tr> <td>allocator_type get_allocator();</td> <td>It returns the allocated object associated with the string.</td> </tr> </table></endl;> Funcions de cadena C++
| Funció | Descripció |
|---|---|
| int compara (const string& str) | S'utilitza per comparar dos objectes de cadena. |
| longitud int () | S'utilitza per trobar la longitud de la corda. |
| void swap (cadena i cadena) | S'utilitza per intercanviar els valors de dos objectes de cadena. |
| string substr(int pos,int n) | Crea un nou objecte de cadena de n caràcters. |
| mida int () | Retorna la longitud de la cadena en termes de bytes. |
| void redimensiona (int n) | S'utilitza per canviar la mida de la cadena fins a n caràcters. |
| string& substituir (int pos, int len, string& str) | Substitueix la part de la cadena que comença a la posició del caràcter pos i abasta els caràcters len. |
| string& append (const string& str) | Afegeix nous caràcters al final d'un altre objecte de cadena. |
| char& at(int pos) | S'utilitza per accedir a un caràcter individual a la posició especificada. |
| int find(cadena&str,int pos,int n) | S'utilitza per trobar la cadena especificada al paràmetre. |
| int find_first_of (cadena& str, int pos, int n) | S'utilitza per trobar la primera ocurrència de la seqüència especificada. |
| int find_first_not_of (cadena& str, int pos, int n ) | S'utilitza per cercar a la cadena el primer caràcter que no coincideix amb cap dels caràcters especificats a la cadena. |
| int trobar_últim_de(cadena&str,int pos,int n) | S'utilitza per cercar a la cadena l'últim caràcter de la seqüència especificada. |
| int find_last_not_of(string&str,int pos) | Cerca l'últim caràcter que no coincideix amb la seqüència especificada. |
| cadena i inserir () | Insereix un caràcter nou abans del caràcter indicat per la posició pos. |
| int mida_màx () | Troba la longitud màxima de la cadena. |
| void push_back (char ch) | Afegeix un nou caràcter ch al final de la cadena. |
| void pop_back() | Elimina un darrer caràcter de la cadena. |
| cadena i assignar () | Assigna un nou valor a la cadena. |
| int còpia (cadena i cadena) | Copia el contingut de la cadena en una altra. |
| char& back() | Retorna la referència de l'últim caràcter. |
| Comença l'iterador() | Retorna la referència del primer caràcter. |
| capacitat int () | Retorna l'espai assignat per a la cadena. |
| const_iterator cbegin() | Apunta al primer element de la cadena. |
| const_iterator cend() | Apunta a l'últim element de la cadena. |
| buit clar () | Elimina tots els elements de la cadena. |
| const_reverse_iterator crbegin() | Apunta a l'últim caràcter de la cadena. |
| const_char* dades() | Copia els caràcters de la cadena en una matriu. |
| bool buit() | Comprova si la cadena està buida o no. |
| cadena i esborra () | Elimina els caràcters tal com s'especifica. |
| cara& frontal() | Retorna una referència del primer caràcter. |
| cadena&� operador+=() | Afegeix un caràcter nou al final de la cadena. |
| cadena& operador=() | Assigna un nou valor a la cadena. |
| operador de caràcters[](pos) | Recupera un caràcter a la posició especificada pos. |
| int rfind() | Cerca l'última ocurrència de la cadena. |
| final de l'iterador () | Fa referència a l'últim caràcter de la cadena. |
| reverse_iterator rend() | Apunta al primer caràcter de la cadena. |
| void shrink_to_fit() | Redueix la capacitat i la fa igual a la mida de la corda. |
| char* c_str() | Retorna el punter a una matriu que conté una seqüència de caràcters acabada nul·la. |
| const_reverse_iterator crend() | Fa referència al primer caràcter de la cadena. |
| reverse_iterator rbegin() | Fa referència a l'últim caràcter de la cadena. |
| reserva nul·la (inr len) | Demana un canvi de capacitat. |
| allocator_type get_allocator(); | Retorna l'objecte assignat associat a la cadena. |