C Program to Count All Occurrence of a Character in a String

Write a C Program to Count All Occurrence of a Character in a String with example.

C Program to Count All Occurrence of a Character in a String Example 1

This program allows the user to enter a string (or character array), and a character value. Next, the C program will search and count the total number of times this character has occurred inside a string.

/* C Program to Count All Occurrence of a Character in a String */
 
#include <stdio.h>
#include <string.h>
 
int main()
{
  	char str[100], ch;
  	int i, Count;
  	Count = 0;
 
  	printf("\n Please Enter any String :  ");
  	gets(str);
  	
  	printf("\n Please Enter the Character that you want to Search for :  ");
  	scanf("%c", &ch);
  	
  	for(i = 0; i <= strlen(str); i++)
  	{
  		if(str[i] == ch)  
		{
  			Count++;
 		}
	}
	printf("\n The Total Number of times '%c' has Occured = %d ", ch, Count);
	
  	return 0;
}

In this C Program to Count All Occurrence of a Character in a String, First, we used For Loop to iterate each character in a String.

for(i = 0; i <= strlen(str); i++)
{
	if(str[i] == ch)  
	{
		Count++;  	
	}
}

str[] = tutorial gateway
ch = t
Count = 0

For Loop First Iteration: for(i = 0; i <= strlen(str); i++)

The condition is True because 0 <= 16.

Within the C Programming While Loop, we used If Statement to check whether the str[0] is equal to a user-specified character or not

if(str[i] == ch) => if(t == t)

The above condition is True. So, the compiler will execute the statement inside the If block.

Count++
it means Count = 1

Second Iteration: for(i = 1; 1 <= 16; 1++) – The condition is True because 1 <= 16.

if(str[i] == ch) => if(t == l) – condition is false. So, i value will increment.

Third Iteration: for(i = 2; 2 <= 16; 2++)

if(str[i] == ch) => if(t == t) – condition is True.

Count++
It means Count = 2

Do the same for the remaining iterations.

C Program to count Occurrence of a Character in a String Example 2

This program to Count All Occurrence of a Character is the same as above. Here, we just replaced the For Loop with While Loop.

/* C Program to Count All Occurrence of a Character in a String */
 
#include <stdio.h>
#include <string.h>
 
int main()
{
  	char str[100], ch;
  	int i, Count;
  	i = Count = 0;
 
  	printf("\n Please Enter any String :  ");
  	gets(str);
  	
  	printf("\n Please Enter the Character that you want to Search for :  ");
  	scanf("%c", &ch);
  	
  	while(str[i] != '\0')
  	{
  		if(str[i] == ch)  
		{
  			Count++;
 		}
 		i++;
	}
	printf("\n The Total Number of times '%c' has Occured = %d ", ch, Count);
	
  	return 0;
}

Output

 Please Enter any String :  hello world

 Please Enter the Character that you want to Search for :  l

 The Total Number of times 'l' has Occured = 3

C Program to find All Occurrence of a Character in a String Example 3

This program is the same as the first example, but this time we used the Functions concept to separate the logic.

/* C Program to Count All Occurrence of a Character in a String */
 
#include <stdio.h>
#include <string.h>

int Count_AllCharcater(char str[], char ch);
 
int main()
{
  	char str[100], ch;
  	int Count;
  	Count = 0;
 
  	printf("\n Please Enter any String :  ");
  	gets(str);
  	
  	printf("\n Please Enter the Character that you want to Search for :  ");
  	scanf("%c", &ch);
  	
  	Count = Count_AllCharcater(str, ch);
  	
	printf("\n The Total Number of times '%c' has Occured = %d ", ch, Count);
	
  	return 0;
}

int Count_AllCharcater(char str[], char ch)
{
	int i, Count;
	Count = 0;
	
  	for(i = 0; i <= strlen(str); i++)
  	{
  		if(str[i] == ch)  
		{
  			Count++;
 		}
	}
	return Count;
}

Output

 Please Enter any String :  learn c programming with many examples

 Please Enter the Character that you want to Search for :  a

 The Total Number of times 'a' has Occured = 4