C program to Toggle Case of all Characters in a String

How to write a C program to Toggle Case of all Characters in a String with example. 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 C For Loop to iterate each character in that C string. And converts the Lowercase character to uppercase, and uppercase character to lowercase.

We already explained the steps involved in C Program to Convert Lowercase to Uppercase and C Program to Convert Upper case to Lowercase in two different articles. 

#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;
}

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

This program to toggle character in a string is the same as above, but this time we are using ASCII Table values inside the C Else If Statement.

#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;
}

 Please Enter any String to Toggle :  TutoriAL GATEwaY

 The Given String after Toggling Case of all Characters = tUTORIal gateWAy

C Program to Toggle Cases in a String Using While Loop

This C program is the same as above, but this time we are using the C language While Loop.

#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;
}

 Please Enter any String to Toggle :  C PrograMMIng

 The Given String after Toggling Case of all Characters = c pROGRAmmiNG

Program to Toggle Case of all Characters in a String Using Functions

This toggle character case in a string program uses the Functions concept to separate the logic from the main program. Also, refer to the C Program to Remove White Spaces from a String article.

#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;
		}
  	}
}

Please Enter any String to Toggle :  Learn C PROGRAMMING foR FreE

 The Given String after Toggling Case of all Characters = lEARN c programming FOr fREe