C program to check whether a character is alphabet or not

Write a C program to input a character from user and check whether the given character is alphabet or not using if else. How to check whether a character is alphabet or not in C programming. Logic to check if a character is alphabet or not in C program.

Example
Input

Input character: a

Output

'a' is alphabet

Required knowledge

Basic C programming, Relational operators, Logical operators, If else

Logic to check alphabets

In C every printable and non-printable symbol is treated as a character and has an ASCII value. ASCII value is unique integer value for every character. It is used to represent a character in memory. In memory every character is stored as an integer.

One of the beginner way to tackle the problem is check input for every alphabet characters. However, I will not explain this method neither I recommend you to try.

An input character is alphabet if it is in between a-z or A-Z.
Note: a and A both are different and have different ASCII values.

Step by step descriptive logic to check alphabets.

  1. Input a character from user. Store it in some variable say ch.
  2. Check if((ch >= 'a') && (ch <= 'z')) or if((ch >= 'A') && (ch <= 'Z')). Then it is alphabet otherwise not.

Let us implement above logic through C program.

Program to check alphabets

/**
 * C program to check whether a character is alphabet or not
 */

#include <stdio.h>

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

    if((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z'))
    {
        printf("Character is an ALPHABET.");
    }
    else
    {
        printf("Character is NOT ALPHABET.");
    }

    return 0;
}

Note: You can also use ASCII values to check alphabets. ASCII value of a=97, z=122, A=65 and Z=90.

Program to check alphabets using ASCII value

/**
 * C program to check whether a character is alphabet or not
 */

#include <stdio.h>

int main()
{
    char ch;

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


    if((ch >= 97 && ch <= 122) || (ch >= 65 && ch <= 90))
    {
        printf("Character is an ALPHABET.");
    }
    else
    {
        printf("Character is NOT ALPHABET.");
    }

    return 0;
}

Enhance your skills by learning other approach to solve the given program.

Learn more - Program to check alphabets using conditional operator.

Output

Enter any character: b
Character is an ALPHABET.

Happy coding 😉

About Pankaj

Pankaj Prakash is the founder, editor and blogger at Codeforwin. He loves to learn new techs and write programming articles especially for beginners. He works at Vasudhaika Software Sols. as a Software Design Engineer and manages Codeforwin. In short Pankaj is Web developer, Blogger, Learner, Tech and Music lover.

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