Check whether a character is an alphabet or not in C

Understanding Alphabets

An alphabet is any letter from A to Z (both uppercase and lowercase). Any other character is not considered an alphabet.

We will explore three different methods to check whether a character is an alphabet or not in C.

Method 1: Using if-else

This method checks if the character falls within the range of alphabets.

#include <stdio.h>


void checkAlphabet(char ch) {
    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);
    }
}

int main() {
    char ch;
    printf("Enter a character: ");
    scanf(" %c", &ch);
    checkAlphabet(ch);
    return 0;
}
            

Method 2: Using ASCII Values

This method checks the ASCII values of the character.

#include <stdio.h>

void checkAlphabet(char ch) {
    if ((ch >= 65 && ch <= 90) || (ch >= 97 && ch <= 122)) {
        printf("%c is an alphabet\n", ch);
    } else {
        printf("%c is not an alphabet\n", ch);
    }
}

int main() {
    char ch;
    printf("Enter a character: ");
    scanf(" %c", &ch);
    checkAlphabet(ch);
    return 0;
}
            

Method 3: Using a Function

This method defines a function to check if a character is an alphabet.

#include <stdio.h>
#include <stdbool.h>


bool isAlphabet(char ch) {
    return ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z'));
}

void checkAlphabet(char ch) {
    if (isAlphabet(ch)) {
        printf("%c is an alphabet\n", ch);
    } else {
        printf("%c is not an alphabet\n", ch);
    }
}

int main() {
    char ch;
    printf("Enter a character: ");
    scanf(" %c", &ch);
    checkAlphabet(ch);
    return 0;
}