C Programs

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Decision Making Programs in C

Check whether a character is alphabet or not

Introduction

In C programming, characters can be classified as alphabets, digits, or special symbols.
An alphabet is any character from A–Z or a–z.

We can check this using:

• ASCII values (65–90 for A–Z and 97–122 for a–z)
• or using relational operators in C (if (ch >= 'A' && ch <= 'Z'))

C Program: Check Whether a Character is an Alphabet or Not

#include <stdio.h>
 
int main() {
    char ch;
 
    // Input a character
    printf("Enter a character: ");
    scanf("%c", &ch);
 
    // Check whether it is an alphabet
    if ((ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z')) {
        printf("%c is an alphabet.\n", ch);
    } else {
        printf("%c is not an alphabet.\n", ch);
    }
 
    return 0;
}
    

 
OUTPUT 1 :
Enter a character: A
A is an alphabet.

OUTPUT 2 :
Enter a character: 9
9 is not an alphabet.

OUTPUT 3 :
Enter a character: $
$ is not an alphabet.

Explanation

1. User enters a single character.
2. Program checks:
   • If it lies between 'A' and 'Z' (uppercase alphabets)
   • OR between 'a' and 'z' (lowercase alphabets)
3. If condition is true → it's an alphabet; else → not an alphabet.