C program to Toggle each characters in a string

C – Strings : 

Strings are actually one-dimensional array of characters terminated by a null character ‘\0’. Thus a null-terminated string contains the characters that comprise the string followed by a null.

String is a sequence of characters. char data type is used to represent one single character in C. So if you want to use a string in your program then you can use an array of characters.

The declaration and definition of the string using an array of chars is similar to declaration and definition of an array of any other data type.

Any string ends with a terminating null character ‘\0’. An array definition in such a way should include null character ‘\0’ as the last element.

Here is source code of the C program to Toggle each characters in a string. The C program is successfully compiled and run(on Codeblocks) on a Windows system. The program output is also shown in below.

SOURCE CODE : :

/*  C program to Toggle each characters in a string  */

#include <stdio.h>

int main()
{
    char    str[100];
    int     counter;

    printf("\nEnter a string: ");
    gets(str);

    // toggle each string characters
    for(counter=0;str[counter]!=NULL;counter++)
    {
        if(str[counter]>='A' && str[counter]<='Z')
            str[counter]=str[counter]+32;   //convert into lower case
        else if(str[counter]>='a' && str[counter]<='z')
            str[counter]=str[counter]-32;   //convert into upper case
    }

    printf("\nString after toggle each characters: [ %s ]\n",str);
    return 0;
}

OUTPUT : :

/*  C program to Toggle each characters in a string  */

Enter a string: Hello CodezClub

String after toggle each characters: [ hELLO cODEZcLUB ]

Process returned 0

Above is the source code for C program to Toggle each character in a string which is successfully compiled and run on Windows System.The Output of the program is shown above .