Enter a string with space: Hello Developer's You entered: Hello Developer's

#include <stdio.h>
#include <ctype.h>

int main()
{
    char alphabet;

    printf("Enter an alphabet : ");
    alphabet = getchar();

    printf("Reversed case : ");
    if (islower(alphabet))
    {
        putchar(toupper(alphabet));
    }
    else
    {
        putchar(tolower(alphabet));
    }

    return 0;
}

OUTPUT

Enter an alphabet : a
Reversed case : A