Program to count occurrence of a given character in a string

Given a string and a character, the task is to make a function which count occurrence of the given character in the string.

Examples: 

Input : str = "geeksforgeeks"
         c = 'e'
Output : 4
'e' appears four times in str.

Input : str = "abccdefgaa"
          c = 'a' 
Output : 3
'a' appears three times in str.

Implementation:

C++

// C++ program to count occurrences of a given
// character
#include <iostream>
#include <string>
using namespace std;

// Function that return count of the given
// character in the string
int count(string s, char c)
{
    // Count variable
    int res = 0;

    for (int i=0;i<s.length();i++)

        // checking character in string
        if (s[i] == c)
            res++;

    return res;
}

// Driver code
int main()
{
    string str= "geeksforgeeks";
    char c = 'e';
    cout << count(str, c) << endl;
    return 0;
}

Java

// JAVA program to count occurrences
// of a character

class GFG
{
    // Method that return count of the given
    // character in the string
    public static int count(String s, char c)
    {
        int res = 0;

        for (int i=0; i<s.length(); i++)
        {
            // checking character in string
            if (s.charAt(i) == c)
            res++;
        }
        return res;
    }

    // Driver method
    public static void main(String args[])
    {
        String str= "geeksforgeeks";
        char c = 'e';
        System.out.println(count(str, c));
    }
}

Python3

# Python program to count occurrences
# of a given character

# Method that return count of the
# given character in the string
def count(s, c) :

    # Count variable
    res = 0

    for i in range(len(s)) :

        # Checking character in string
        if (s[i] == c):
            res = res + 1
    return res


# Driver code
str= "geeksforgeeks"
c = 'e'
print(count(str, c))

# This code is contributed by "rishabh_jain".

C#

// C# program to count occurrences
// of a character
using System;

public class GFG {

    // Method that return count of the given
    // character in the string
    public static int count(string s, char c)
    {
        int res = 0;

        for (int i = 0; i < s.Length; i++)
        {

            // checking character in string
            if (s[i] == c)
            res++;
        }

        return res;
    }

    // Driver method
    public static void Main()
    {
        string str = "geeksforgeeks";
        char c = 'e';

        Console.WriteLine(count(str, c));
    }
}

// This code is contributed by Sam007.

PHP

<?php
// PHP program to count
// occurrences of a given
// character

// Function that return count of
// the given character in the string
function count($s, $c)
{

    // Count variable
    $res = 0;

    for ($i = 0; $i < strlen($s); $i++)

        // checking character in string
        if ($s[$i] == $c)
            $res++;

    return $res;
}

    // Driver Code
    $str= "geeksforgeeks";
    $c = 'e';
    echo count($str, $c) ;
    return 0;

// This code is contributed by nitin mittal.
?>

Javascript

<script>
// JAVASCRIPT program to count occurrences
// of a character
    // Method that return count of the given
    // character in the string
    function count(s, c)
    {
        let res = 0;

        for (let i = 0; i < s.length; i++)
        {
            // checking character in string
            if (s.charAt(i) == c)
            res++;
        }
        return res;
    }

    // Driver method
        let str= "geeksforgeeks";
        let c = 'e';
        document.write(count(str, c));

 // This code is contributed by shivanisinghss2110
 </script>

Output

4

Time Complexity: O(len), where len is the size of the string given.
Auxiliary Space: O(1)

Implementation using Direct Function in C++:

C++

// CPP program to count occurrences of
// a character using library
#include<bits/stdc++.h>
using namespace std;

// Driver code
int main()
{
    string str = "geeksforgeeks";
    char c = 'e';

    // Count returns number of occurrences of
    // c between two given positions provided
    // as two iterators.
    cout << count(str.begin(), str.end(), c);
    return 0;
}

Output

4

Time Complexity: O(len), where len is the size of the string given.
Auxiliary Space: O(1) 

Implementation using recursion:

C++

#include<bits/stdc++.h>
using namespace std;

int countinString(char ch,string s)
{
    // base case;
    if (s.length() == 0)
        return 0;
        int count = 0;

    // checking if the first character of
    // the given string is that character
    // or not
    if (s[0] == ch)
        count++;

        // this will count the occurrence of
        // given character in the string
        // from index 1 to the last
        // index of the string
    count += countinString(ch, s.substr(1));

    return count;
}

int main(){
    string str = "geeksforgeeks";
    char c = 'e';
    cout<<(countinString(c, str));
}

// This code is contributed by shinjanpatra

Java

/*package whatever //do not write package name here */

import java.io.*;

class GFG {
      static int countinString(char ch, String s)
    {
          //base case;
        if(s.length()==0)
            return 0;
          int count = 0;

          //checking if the first character of
          //the given string is that character
          //or not
          if(s.charAt(0)==ch)
          count++;

          //this will count the occurrence of
          //given character in the string
          //from index 1 to the last
          //index of the string
          count+=countinString(ch,s.substring(1));


        return count;
    }
    public static void main (String[] args) {
        String str= "geeksforgeeks";
        char c = 'e';
        System.out.println(countinString(c,str));
    }
}

Python3

def countinString(ch, s):

    # base case;
    if (len(s) == 0):
        return 0
    count = 0

    # checking if the first character of
    # the given string is that character
    # or not
    if (s[0] == ch):
        count += 1

    # this will count the occurrence of
    # given character in the string
    # from index 1 to the last
    # index of the string
    count += countinString(ch, s[1:])

    return count

str = "geeksforgeeks"
c = 'e'
print(countinString(c, str))

# This code is contributed by shinjanpatra

C#

/*package whatever //do not write package name here */
using System;
public class GFG {
      static int countinString(char ch, String s)
    {
          // base case;
        if(s.Length == 0)
            return 0;
          int count = 0;

          // checking if the first character of
          // the given string is that character
          // or not
          if(s[0] == ch)
          count++;

          // this will count the occurrence of
          // given character in the string
          // from index 1 to the last
          // index of the string
          count += countinString(ch,s.Substring(1));


        return count;
    }

  // Driver code
    public static void Main(String[] args) {
        String str= "geeksforgeeks";
        char c = 'e';
        Console.WriteLine(countinString(c,str));
    }
}

// This code is contributed by umadevi9616

Javascript

<script>
/*package whatever //do not write package name here */

    function countinString( ch, s)
    {
        // base case;
        if (s.length == 0)
            return 0;
        var count = 0;

        // checking if the first character of
        // the given string is that character
        // or not
        if (s[0] == ch)
            count++;

        // this will count the occurrence of
        // given character in the string
        // from index 1 to the last
        // index of the string
        count += countinString(ch, s.substring(1));

        return count;
    }

        var str = "geeksforgeeks";
        var c = 'e';
        document.write(countinString(c, str));

// This code is contributed by gauravrajput1
</script>

Output

4

Time Complexity: O(len), where len is the size of the string given.

Auxiliary Space: O(len), where len is the size of the string given.

This article is contributed by Sahil Rajput. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.