C Program to Remove All Duplicate Characters in a String

C program to remove all duplicate characters in a string; Through this tutorial, we will learn how to remove all duplicate characters in a string using for loop, while loop and function in c programs.

Programs and Algorithm to Remove All Duplicate Characters From String in C

Algorithm and programs to remove all duplicate characters in a string using for loop, while loop and function in c:

• Algorithm to Remove All Duplicate Characters in a String
• C Program to Remove All Duplicate Characters in a String using For Loop
• C Program to Remove All Duplicate Characters in a String using While Loop
• C Program to Remove All Duplicate Characters in a String using Function

Algorithm to Remove All Duplicate Characters in a String

Use the following algorithm to write a program to remove the duplicate character from a string; as follows:

1. Start program.
2. Take input string from user, store it in some variable.
3. Find and remove all repeated characters of the given string.
4. Print result
5. End program

C Program to Remove All Duplicate Characters in a String using For Loop

/* C Program to Remove All Duplicate Character in a String */

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

int main()
{
  	char str[100];
  	int i, j, k;

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

  	for(i = 0; i < strlen(str); i++)
  	{
  		for(j = i + 1; str[j] != '\0'; j++)
  		{
  			if(str[j] == str[i])
			{
  				for(k = j; str[k] != '\0'; k++)
				{
					str[k] = str[k + 1];
				}
 			}
		}
	}

	printf("\n The Final String after Removing All Duplicates = %s ", str);

  	return 0;
}

The output of the above c program; as follows:

The Final String after Removing All Duplicates = welcom t prgaminus 

C Program to Remove All Duplicate Characters in a String using While Loop

/* C Program to Remove All Duplicate Character in a String */

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

int main()
{
  	char str[100];
  	int i, j, k;
  	i = 0;

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

  	while(i < strlen(str))
  	{
  		j = i + 1;

  		while(str[j] != '\0')
  		{
  			if(str[j] == str[i])
			{
				k = j;

  				while(str[k] != '\0')
				{
					str[k] = str[k + 1];
					k++;
				}
 			}
 			j++;
		}
		i++;
	}

	printf("\n The Final String after Removing All Duplicates = %s ", str);

  	return 0;
}

The output of the above c program; as follows:

Please Enter any String :  c programmer
The Final String after Removing All Duplicates = c progame 

C Program to Remove All Duplicate Characters in a String using Function

/* C Program to Remove All Duplicate Character in a String */

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

void Remove_AllOccurrence(char *str);

int main()
{
  	char str[100];

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

  	Remove_AllOccurrence(str);

	printf("\n The Final String after Removing All Duplicates = %s ", str);

  	return 0;
}

void Remove_AllOccurrence(char *str)
{
	int i, j, k;

	for(i = 0; i < strlen(str); i++)
  	{
  		for(j = i + 1; str[j] != '\0'; j++)
  		{
  			if(str[j] == str[i])
			{
  				for(k = j; str[k] != '\0'; k++)
				{
					str[k] = str[k + 1];
				}
 			}
		}
	}
}

The output of the above c program; as follows:

Please Enter any String :  c programmer
The Final String after Removing All Duplicates = c progame 

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