C Language Reference Manual

Comprehensive Collection of C Programming Examples

C program checks if a character is a letter

In this example, you will learn to check if the character entered by the user is a letter.To understand this example, you should understand the followingC language programming

• Topic:

• C language programming operators

C if ... else statement127In C language programming, a character variable saves the ASCII value (0 to

integer), not the character itself.97or122The ASCII value of lowercase letters is65or90.

The ASCII value of uppercase letters is97or122If the ASCII value of the character entered by the user is within65or90 to

Program checks if a number is within the range

#include <stdio.h>
int main() {
　　　　char c;
　　　　printf("Enter a character: ");
　　　　scanf("%c", &c);
　　　　if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
　　　　　　　　printf("%c is a letter.", c);
　　　　else
　　　　　　　　printf("%c is not a letter.", c);
　　　　return 0;
}

Output Result

Enter a character:　*
*　Is not a letter.

In the program, replace with 'a'.97Replace with 'z'.122Similarly, replace with 'A'.65Replace with 'Z'.90.

Note:Suggested to use this isalpha() function to check if a character is a letter.

Comprehensive Collection of C Programming Examples