C Program to check whether the Character is Alphabet or Digit

Write a C Program to check whether the Character is Alphabet or Digit by using the Built-in function isalpha, isdigit, and also not using any built-in function.

C Program to check whether the Character is Alphabet or Digit

This program allows the user to enter one character. Then it will check whether the user-specified character is an Alphabet or a digit.

#include <stdio.h>

int main()
{
  char ch;
  printf(" Please Enter any character :  ");
  scanf("%c", &ch);
  
  if( (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') )
  {
  	printf("\n %c is an Alphabet", ch);  	
  }
  else if (ch >= '0' && ch <= '9')
  {
  	printf("\n %c is a Digit", ch);  	
  }    
  else
    printf("\n %c is not an Alphabet, or a Digit", ch);
  
  return 0;
}

Let us check whether 7 is an Alphabet or Digit

 Please Enter any character :  7

 7 is a Digit

Let us check whether $ is an Alphabet or not (which is not TRUE)

 Please Enter any character :  $

 $ is not an Alphabet, or a Digit

Check whether the Character is Alphabet or Digit 2

In this program, we are using the ASCII values to check whether the input character is Alphabet or Digit. I suggest you refer to the ASCII Table to understand the values of each character in C Programming.

#include <stdio.h>

int main()
{
  char ch;
  printf(" Please Enter any character :  ");
  scanf("%c", &ch);
  
  if (ch >= 48 && ch <= 57)
  {
  	printf("\n %c is a Digit", ch);  	
  }
  else if ( (ch >= 65 && ch <= 90) || (ch >= 97 && ch <= 122) )
  {
  	printf("\n %c is an Alphabet", ch);  	
  }    
  else
    printf("\n %c is not an Alphabet, or a Digit", ch);
  
  return 0;
}

 Please Enter any character :  7

 7 is a Digit

Let us check whether # is an Alphabet or not (Not TRUE)

 Please Enter any character :  #

 # is not an Alphabet, or a Digit

Let us check whether g is an Alphabet or not (TRUE)

 Please Enter any character :  g

 g is an Alphabet

In this program, we are using the built-in functions isalpha and isdigit to check whether the input character is Alphabet or Digit

#include <stdio.h>
#include<ctype.h>

int main()
{
  char ch;
  printf(" Please Enter any character :  ");
  scanf("%c", &ch);
  
  if (isdigit(ch))
  {
  	printf("\n %c is a Digit", ch);  	
  }
  else if ( isalpha(ch) )
  {
  	printf("\n %c is an Alphabet", ch);  	
  }    
  else
    printf("\n %c is not an Alphabet, or a Digit", ch);
  
  return 0;
}

 Please Enter any character :  @

 @ is not an Alphabet, or a Digit