Program to Search a Character in a String

Last Updated : 25 Mar, 2025

Given a character ch and a string s, the task is to find the index of the first occurrence of the character in the string. If the character is not present in the string, return -1.

Examples:

Input: s = "geeksforgeeks", ch = 'k'
Output: 3
Explanation: The character 'k' is present at index 3 and 11 in "geeksforgeeks", but it first appears at index 3.
Input: s = "geeksforgeeks", ch = 'z'
Output: -1
Explanation: The character 'z' is not present in "geeksforgeeks".

Table of Content

Approach - By traversing the string - O(n) Time and O(1) Space

The idea is to traverse the input string s and for each character, check if it is equal to the character we are searching for. If we find a match, return the index of the current character.
If we reach the end of the string without finding any occurrence of the character, return -1.

C++

// C++ program to search a character in a string  #include <iostream> using namespace std;  // function to find the first occurrence of ch in s int findChar(string &s, char ch) {     int n = s.length();     for (int i = 0; i < n; i++) {          // If the current character is equal to ch,         // return the current index         if (s[i] == ch)             return i;     }      // If we did not find any occurrence of ch,     // return -1     return -1; }  int main() {     string s = "geeksforgeeks";     char ch = 'k';      cout << findChar(s, ch) << "\n";     return 0; }

// C program to search a character in a string  #include <stdio.h> #include <string.h>  // function to find the first occurrence of ch in s int findChar(char *s, char ch) {     int n = strlen(s);     for (int i = 0; i < n; i++) {                // If the current character is equal to ch,          // return the current index         if (s[i] == ch)             return i;     }      // If we did not find any occurrence of ch,     // return -1     return -1; }  int main() {     char s[] = "geeksforgeeks";     char ch = 'k';        printf("%d\n", findChar(s, ch));     return 0; }

Java

// Java program to search a character in a string  class GfG {        // function to find the first occurrence of ch in s     static int findChar(String s, char ch) {         int n = s.length();         for (int i = 0; i < n; i++) {                        // If the current character is equal to ch,              // return the current index             if (s.charAt(i) == ch)                 return i;         }          // If we did not find any occurrence of ch,         // return -1         return -1;     }      public static void main(String[] args) {         String s = "geeksforgeeks";         char ch = 'k';                System.out.println(findChar(s, ch));     } }

Python

# Python program to search a character in a string  # function to find the first occurrence of ch in s def findChar(s, ch):     n = len(s)     for i in range(n):                # If the current character is equal to ch,          # return the current index         if s[i] == ch:             return i      # If we did not find any occurrence of ch,     # return -1     return -1  if __name__ == "__main__":     s = "geeksforgeeks"     ch = 'k'        print(findChar(s, ch))

// C# program to search a character in a string  using System;  class GfG {          // function to find the first occurrence of ch in s     static int findChar(string s, char ch) {         int n = s.Length;         for (int i = 0; i < n; i++) {                        // If the current character is equal to ch,              // return the current index             if (s[i] == ch)                 return i;         }          // If we did not find any occurrence of ch,         // return -1         return -1;     }      static void Main(string[] args) {         string s = "geeksforgeeks";         char ch = 'k';          Console.WriteLine(findChar(s, ch));     } }

JavaScript

// JavaScript program to search a character in a string  // function to find the first occurrence of ch in s function findChar(s, ch) {     let n = s.length;     for (let i = 0; i < n; i++) {                // If the current character is equal to ch,          // return the current index         if (s[i] === ch)             return i;     }      // If we did not find any occurrence of ch,     // return -1     return -1; }  let s = "geeksforgeeks"; let ch = 'k';  console.log(findChar(s, ch));

Output

Approach - By Using in-built library functions - O(n) Time and O(1) Space

We can also use inbuilt library functions to search for a character in a string. This makes the search simple and easier to implement.

C++

#include <iostream> #include <string>  using namespace std;  int findCharacterIndex(const string& s, char ch) {     size_t idx = s.find(ch);      if (idx != string::npos) {         return idx;     } else {         return -1;     } }  int main() {     string s = "geeksforgeeks";     char ch = 'k';      int index = findCharacterIndex(s, ch);     cout << index << endl;      return 0; }

#include <stdio.h> #include <string.h>  int findCharacterIndex(const char* s, char ch) {     char* ptr = strchr(s, ch);     if (ptr != NULL) {         return ptr - s;     } else {         return -1;     } }  int main() {     const char* s = "geeksforgeeks";     char ch = 'k';      int index = findCharacterIndex(s, ch);     printf("%d\n", index);      return 0; }

Java

public class GfG{     public static int findCharacterIndex(String s, char ch) {         int idx = s.indexOf(ch);         return (idx != -1) ? idx : -1;     }      public static void main(String[] args) {         String s = "geeksforgeeks";         char ch = 'k';          int index = findCharacterIndex(s, ch);         System.out.println(index);     } }

Python

def find_character_index(s, ch):     idx = s.find(ch)     return idx   s = "geeksforgeeks" ch = 'k'  index = find_character_index(s, ch) print(index)

using System;  class GfG {     static int FindCharacterIndex(string s, char ch) {         int idx = s.IndexOf(ch);         return idx != -1 ? idx : -1;     }      static void Main() {         string s = "geeksforgeeks";         char ch = 'k';          int index = FindCharacterIndex(s, ch);         Console.WriteLine(index);     } }

JavaScript

function findCharacterIndex(s, ch) {     let idx = s.indexOf(ch);     return idx !== -1 ? idx : -1; }  let s = "geeksforgeeks"; let ch = 'k';  let index = findCharacterIndex(s, ch); console.log(index);