character input

Problem State: Write down macro definitions for the following:
1. To test whether a character is a small case letter or not.
2. To test whether a character is an upper case letter or not.
3. To test whether a character is an alphabet or not. Make use of the macros you defined in 1 and 2 above.
4. To obtain the bigger of two numbers.

Problem Statement Analysis

1. We need to write 4 Macro definitions.
2. We must write macros to find upper and lower case, and then make use of these two macros to find if user entered character is alphabet or not.
3. We can find biggest of 2 numbers by using Ternary / conditional operator in macro expansion.

Video Tutorial: Using Macros Check For Uppercase / Lowercase and Alphabet or Not and Biggest of 2 Numbers: C Program

[youtube https://www.youtube.com/watch?v=EEGLYe2buxk]

YouTube Link: https://www.youtube.com/watch?v=EEGLYe2buxk [Watch the Video In Full Screen.]

Source Code: Using Macros Check For Uppercase / Lowercase and Alphabet or Not and Biggest of 2 Numbers: C Program

#include<stdio.h>

#define isUPPER(ch) ( ch >= 'A' && ch <= 'Z' )
#define isLOWER(ch) ( ch >= 'a' && ch <= 'z' )
#define isALPHABET(ch) ( isUPPER(ch) || isLOWER(ch) )
#define BIGGEST(a, b) ( ( a > b ) ? \
                       printf("%d is the biggest\n", a) : \
                       printf("%d is the biggest\n", b) )

int main()
{
    int a, b, repeat;
    char ch, choice;

    do
    {
        printf("1. Check if entered character is upper or lower case\n");
        printf("2. Check if entered character is alphabet or not\n");
        printf("3. Find biggest of 2 numbers\n");

        printf("\nEnter your choice\n");
        scanf(" %c", &choice);

        switch(choice)
        {
            case '1': printf("\nEnter a character\n");
                      scanf(" %c", &ch);

                      if( isUPPER(ch) )
                      {
                          printf("Entered character is upper case letter\n");
                      }
                      else if( isLOWER(ch) )
                      {
                          printf("Entered character is lower case letter\n");
                      }
                      else
                      {
                          printf("Please enter a valid alphabet\n");
                      }

                      break;
            case '2': printf("\nEnter a character\n");
                      scanf(" %c", &ch);

                      if( isALPHABET(ch) )
                      {
                          printf("Entered character is an alphabet\n");
                      }
                      else
                      {
                          printf("Entered character is not an alphabet\n");
                      }
                      break;
            case '3': printf("\nEnter 2 numbers\n");
                      scanf("%d%d", &a, &b);

                      BIGGEST(a, b);

                      break;
            default:  printf("\nPlease enter valid choice\n");
        }

        printf("\n\nDo you want to continue? Ans: 0 or 1\n");
        scanf("%d", &repeat);

        printf("\n");
        fflush(stdin);

    }while(repeat);

    return 0;
}

Output:
1. Check if entered character is upper or lower case
2. Check if entered character is alphabet or not
3. Find biggest of 2 numbers

Enter your choice
1

Enter a character
S
Entered character is upper case letter