C program to check whether a character is Uppercase or Lowercase

Example
Input

Input character: C

Output

'C' is uppercase alphabet

/**
 * C program to check whether a character is uppercase or lowercase 
 */

#include <stdio.h>

int main()
{
    char ch;

    /* Input character from user */
    printf("Enter any character: ");
    scanf("%c", &ch);


    if(ch >= 'A' && ch <= 'Z')
    {
        printf("'%c' is uppercase alphabet.", ch);
    }
    else if(ch >= 'a' && ch <= 'z')
    {
        printf("'%c' is lowercase alphabet.", ch);
    }
    else
    {
        printf("'%c' is not an alphabet.", ch);
    }

    return 0;
}

/*
Output :

Enter any character: C
'C' is uppercase alphabet.
*/

Program to check uppercase or lowercase characters using library functions

/**
 * C program to check whether a character is uppercase 
 * or lowercase using inbuilt library functions
 */

#include <stdio.h>
#include <ctype.h> /* Used for isupper() and islower() */

int main()
{
    char ch;

    /* Input character from user */
    printf("Enter any character: ");
    scanf("%c", &ch);

    if(isupper(ch))
    {
        printf("'%c' is uppercase alphabet.", ch);
    }
    else if(islower(ch))
    {
        printf("'%c' is lowercase alphabet.", ch);
    }
    else
    {
        printf("'%c' is not an alphabet.", ch);
    }

    return 0;
}

/*
Output :

Enter any character: C
'C' is uppercase alphabet.
*/