Check whether a Character is an Alphabet or not in C

Exercise:

Write a C Program to check whether a character is an alphabet or not.

Click Here to View the Solution!
#include <stdio.h>      
int main() {
    char ch;
    printf("Enter a character: ");
    scanf("%c", &ch);

    if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z'))
        printf("%c is an alphabet.", ch);
    else
        printf("%c is not an alphabet.", ch);
    return 0;
}
Click Here to View the Output!
Enter a character: f
f is an alphabet. 
Click Here to View the Explanation!
  • This program is used to determine whether an entered character is an Alphabet.
  • In the main method, the program requests the user to enter a character and stores it in a character variable ch using the scanf() function.
  • In C language programming, each character has an equivalent ASCII value. For lowercase alphabets the range starts from a = 97 to z = 122 and for uppercase alphabets the range starts from A = 65 to Z = 90.
  • Initially, in the if statement, the program compares c with a and z along with A and Z like (ch >= ‘a’ && ch <= ‘z’ || ch >= ‘A’ && ch<= ‘Z’). Both conditions for the lowercase and uppercase alphabets are separated by the || OR operator. If either of the conditions are true, the message ch is an alphabet is printed.
  • If the condition is false, the else statement is executed which prints the message ch is not an alphabet.
  • This can also be done using the isalpha() function in C.