Check Whether a Character is an Alphabet or Not

In this example, we take one character input from user and check whether a character is alphabet or not.

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

To check character is alphabet or not we validate inputted character is between below two range or not :

1. For lowercase alphabets: >= "a" and <= "z"
2. For uppercase alphabets: >= "A" and <= "Z"

Example :

	
#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\n",ch);
    else
        printf("%c is not an alphabet\n",ch);
    return 0;
}
	

Output :

	
//Output :- 1
Enter a character: a
a is an alphabet
//Output :- 2
Enter a character: ?
? is not an alphabet
	

C Program to Check Whether a Character is an Alphabet or Not Using ASCII Value

The ASCII value of ‘a’ is 97, ‘z’ is 122, ‘A’ is 65 and ‘Z’ is 90.

	
#include <stdio.h>
int main()
{
    char ch;
    printf("Enter a character: ");
    scanf(" %c",&ch);
if((ch >= 97 && ch <= 122) || (ch >= 65 && ch <= 90))

    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 :

	
Enter a character: Z
Z is an alphabet
	

C Program to Check Whether a Character is an Alphabet or Not Using isalpha() Function

Function isalpha() takes a single argument in the form of an integer and returns an integer value. Here, Function isalpha() takes a single argument in the form of an integer and returns an integer value.

	
#include <stdio.h>
#include <ctype.h>
int main()
{
    char c;

    printf("Enter a character: ");
    scanf("%c", &c);

    if (isalpha(c) == 0)
            printf("%c is not an alphabet.", c);
    else
            printf("%c is an alphabet.", c);

    return 0;
}
	

Output :

	
Enter a character: 5
5 is not an alphabet