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

C program to replace all occurrences of a character in a string; Through this tutorial, we will learn how to replace all occurrences of a character in a string using for loop, while loop and functions in c programs.

Programs and Algorithm To Replace All Occurrence of a Character in a String in C

• Algorithm To Replace All Occurrence of a Character in a String
• C Program To Replace All Occurrence of a Character in a String using For Loop
• C Program To Replace All Occurrence of a Character in a String using While Loop
• C Program To Replace All Occurrence of a Character in a String using Function

Algorithm To Replace All Occurrence of a Character in a String

Use the following algorithm to write a program to replace all occurrence of a character in a string; as follows:

1. Input string from user, store it in some variable.
2. Input character to replace and character new character from user, store it in some variables.
3. Iterate a loop from start of string str to end.
4. Inside the loop, swap all old character with new character and terminate the loop.
5. Print result.

C Program To Replace All Occurrence of a Character in a String using For Loop

/* C Program to Replace All Occurrence of a Character in a String */

#include <stdio.h>
#include <string.h>

int main()
{
  	char str[100], ch, Newch;
  	int i;

  	printf("\n Please Enter any String :  ");
  	gets(str);

  	printf("Enter a character replace: ");
  	scanf("%c", &ch);

  	getchar();

    printf("\nEnter character to replace  with  %c : ",ch);
  	scanf("%c", &Newch);

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

	printf("\n The Final String after Replacing All Occurrences of '%c' with '%c' = %s ", ch, Newch, str);

  	return 0;
}

The output of the above c program; as follows:

Please Enter any String :  c progr@mmer
Enter a character replace: @
Enter character to replace  with  @ : a
The Final String after Replacing All Occurrences of '@' with 'a' = c programmer 

C Program To Replace All Occurrence of a Character in a String using While Loop

/* C Program to Replace All Occurrence of a Character in a String */

#include <stdio.h>
#include <string.h>

int main()
{
  	char str[100], ch, Newch;
  	int i = 0;

  	printf("\n Please Enter any String :  ");
  	gets(str);

    printf("Enter a character replace: ");
  	scanf("%c", &ch);

  	getchar();

  	printf("\n Please Enter the New Character :  ");
  	scanf("%c", &Newch);

  	while(str[i] != '\0')
  	{
  		if(str[i] == ch)
		{
  			str[i] = Newch;
 		}
 		i++;
	}

	printf("\n The Final String after Replacing All Occurrences of '%c' with '%c' = %s ", ch, Newch, str);

  	return 0;
}

The output of the above c program; as follows:

Please Enter any String :  he@@@o
Enter a character replace: @
Please Enter the New Character :  l
The Final String after Replacing All Occurrences of '@' with 'l' = helllo 

C Program To Replace All Occurrence of a Character in a String using Function

/* C Program to Replace All Occurrences of a Character in a String */

#include <stdio.h>
#include <string.h>

void Replace_AllOccurrence(char *str, char ch, char Newch);

int main()
{
  	char str[100], ch, Newch;
  	int i = 0;

  	printf("\n Please Enter any String :  ");
  	gets(str);

  	printf("Enter a character replace: ");
  	scanf("%c", &ch);

  	getchar();

  	printf("\nEnter character to replace  with  %c : ",ch);
  	scanf("%c", &Newch);

  	Replace_AllOccurrence(str, ch, Newch);

  	printf("\n The Final String after Replacing All Occurrences of '%c' with '%c' = %s ", ch, Newch, str);

  	return 0;
}

void Replace_AllOccurrence(char *str, char ch, char Newch)
{
	int i;

	for(i = 0; str[i] != '\0'; i++)
	{
		if(str[i] == ch)
		{
			str[i] = Newch;
		}
	}
}

The output of the above c program; as follows:

Please Enter any String :  c programming
Enter a character replace: m
Enter character to replace  with  m : @
The Final String after Replacing All Occurrences of 'm' with '@' = c progra@@ing 

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