C program to Toggle Case of all Characters in a String

In this article, We will show you, How to write a C program to Toggle Case of all Characters in a String with example. We already explained the steps involved in Converting Lowercase to Uppercase, and Upper case to Lowercase in two different articles.  To demonstrate the same we are going to use For Loop, While Loop, Functions, and ASCII Values

C program to Toggle Case of all Characters in a String using For Loop

This program allows the user to enter any string or character array. Next, it will use For Loop to iterate each and every character in that string, and convert Lowercase character to uppercase, and uppercase character to lowercase.

/* C program to Toggle Case of all Characters in a String */

#include <stdio.h>
#include <string.h>
 
int main()
{
  	char Str1[100];
  	int i;
 
  	printf("\n Please Enter any String to Toggle : ");
  	gets(Str1);
  	
  	for (i = 0; Str1[i]!='\0'; i++)
  	{
  		if(Str1[i] >= 'a' && Str1[i] <= 'z')
  		{
  			Str1[i] = Str1[i] - 32;
		}		
  		else if(Str1[i] >= 'A' && Str1[i] <= 'Z')
  		{
  			Str1[i] = Str1[i] + 32;
		}
  	}

  	printf("\n The Given String after Toggling Case of all Characters = %s", Str1);
  	
  	return 0;
}

OUTPUT

C program to Toggle Case of all Characters in a String using ASCII Value

This program is same as above but this time we are using ASCII values inside the Else If Statement. I suggest you to refer ASCII Table to understand the codes

/* C program to Toggle Case of all Characters in a String */

#include <stdio.h>
#include <string.h>
 
int main()
{
  	char Str1[100];
  	int i;
 
  	printf("\n Please Enter any String to Toggle :  ");
  	gets(Str1);
  	
  	for (i = 0; Str1[i]!='\0'; i++)
  	{
  		if(Str1[i] >= 65 && Str1[i] <= 90)
  		{
  			Str1[i] = Str1[i] + 32;
		}
		else if(Str1[i] >= 97 && Str1[i] <= 122)
  		{
  			Str1[i] = Str1[i] - 32;
		}
  	}

  	printf("\n The Given String after Toggling Case of all Characters = %s", Str1);
  	
  	return 0;
}

OUTPUT

C program to Toggle Case of all Characters in a String Using While Loop

This program is same as above but this time we are using While loop (Just replacing For Loop with While Loop). I suggest you to refer While Loop to understand the loop Iteration.

/* C program to Toggle Case of all Characters in a String */

#include <stdio.h>
#include <string.h>
 
int main()
{
  	char Str1[100];
  	int i;
 
  	printf("\n Please Enter any String to Toggle :  ");
  	gets(Str1);
  	
  	i = 0; 
  	while(Str1[i]!='\0')
  	{
  		if(Str1[i] >= 'a' && Str1[i] <= 'z')
  		{
  			Str1[i] = Str1[i] - 32;
		}		
  		else if(Str1[i] >= 'A' && Str1[i] <= 'Z')
  		{
  			Str1[i] = Str1[i] + 32;
		}
		i++;
  	}

  	printf("\n The Given String after Toggling Case of all Characters = %s", Str1);
  	
  	return 0;
}

OUTPUT

C program to Toggle Case of all Characters in a String Using Functions

This program is same as above but this time we are using Functions concept to separate the logic from main program.

/* C program to Toggle Case of all Characters in a String */

#include <stdio.h> 

void String_Toggle(char []);
 
int main()
{
	char str[100];
 
	printf("\n Please Enter any String to Toggle :  ");
	gets(str);
 
	String_Toggle(str);
 
	printf("\n The Given String after Toggling Case of all Characters = %s", str);
 
	return 0;
}
 
void String_Toggle(char Str1[]) 
{
	int i;
 
	for (i = 0; Str1[i]!='\0'; i++)
  	{
  		if(Str1[i] >= 65 && Str1[i] <= 90)
  		{
  			Str1[i] = Str1[i] + 32;
		}
		else if(Str1[i] >= 97 && Str1[i] <= 122)
  		{
  			Str1[i] = Str1[i] - 32;
		}
  	}
}

OUTPUT

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