std::string::rfind in C++ with Examples
The std::string::rfind is a string class member function that is used to search the last occurrence of any character in the string. If the character is present in the string then it returns the index of the last occurrence of that character in the string else it will return string::npos which denotes the pointer is at the end of the string. Header File:
#include < string >
Syntax 1:
rfind(char ch) rfind(string str)
Parameters: This function takes a given character or a string as a parameter, whose index is to be found. Return value: This method returns the position of the last occurrence of that character or first index of the last occurrence of the string. Program 1: Below is the program to illustrate string::rfind(char ch):
CPP
// C++ program to demonstrate // rfind() method #include <cstddef> #include <iostream> #include <string> using namespace std; // Function to return last occurrence // of character in a string void findLastOccurrence(string str, char ch) { // To store the index of the result size_t found; // Function to find the last // occurrence of character ch // in string str found = str.rfind(ch); // If string doesn't have // character ch present in it if (found == string::npos) { cout << "Character " << ch << " is not present in" << " the given string."; } // Else print the position else { cout << "The last occurrence of '" << ch << "' is found at index: " << found << endl; } } // Driver Code int main() { // Given String string str("Welcome to w3wiki!"); // Character to be found char ch = 'e' ; findLastOccurrence(str, ch); } |
Program 2: Below is the program to illustrate string::rfind(string str):
CPP
// C++ program to demonstrate // rfind() method #include <cstddef> #include <iostream> #include <string> using namespace std; // Function to return last occurrence // of string in a string void findLastOccurrence(string str, string s) { // To store the index of the result size_t found; // Function to find the first index // of last occurrence of string s in str found = str.rfind(s); // If string doesn't have // string s present in it if (found == string::npos) { cout << "String '" << s << "' is not present in" << " the given string."; } // Else print the position else { cout << "The first index of last " << "occurrence of '" << s << "' is found at index: " << found << endl; } } // Driver Code int main() { // Given String string str("Welcome to w3wiki!"); // string to be found string s = "to"; findLastOccurrence(str, s); } |
Syntax 2:
rfind(char ch, size_t position); rfind(string s, size_t position);
Parameters: This function takes:
- a given character or a string as a parameter, whose index is to be found.
- a position till where the search is to be performed.
Return value: This method returns the position of the first character of the last match of that given character or string before that position else it returns string::npos Program 3: Below is the program to illustrate string::rfind(char ch, size_t position):
CPP
// C++ program to illustrate the function // string::rfind(char ch, size_t pos) #include <cstddef> #include <iostream> #include <string> using namespace std; // Function to return last occurrence // of character in a string void findLastOccurrence( string str, char ch, size_t position) { // To store the index of the result size_t found; // Function to find the last occurrence // of character ch in str before pos 5 found = str.rfind(ch, position); // If string doesn't have // character ch present in it if (found == string::npos) { cout << "Character " << ch << " is not present in" << " the given string."; } // Else print the position else { cout << "The last occurrence of " << ch << " before position " << position << " is found at index: " << found << endl; } } // Driver Code int main() { // Given String string str("Welcome to w3wiki!"); // Character to be found char ch = 'e' ; // Position till where // the search is to be done size_t position = 5; findLastOccurrence(str, ch, position); } |
Program 4: Below is the program to illustrate string::rfind(string str, size_t position):
CPP
// C++ program to illustrate the function // string::rfind(string str, size_t pos) #include <cstddef> #include <iostream> #include <string> using namespace std; // Function to return last occurrence // of string in a string void findLastOccurrence( string str, string s, size_t position) { // To store the index of result size_t found; // Function to find the last occurrence of // string s in str before given position found = str.rfind(s, position); // If string doesn't have // string s present in it // If string doesn't have // string s present in it if (found == string::npos) { cout << "String " << s << " is not present in" << " the given string."; } // Else print the position else { cout << "The last occurrence of " << s << " before position " << position << " is found at index: " << found << endl; } } // Driver Code int main() { // Given String string str("Welcome to w3wiki!"); // string to be found string s = "to"; // Position till where // the search is to be done size_t position = 5; findLastOccurrence(str, s, position); } |
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