C Programming: Check whether a character is digit or not

Last update on March 20 2025 12:42:35 (UTC/GMT +8 hours)

30. Check Digit Character

Write a program in C to check whether a character is a digit or not.

Sample Solution:

C Code:

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

int main() {
    char TestChar; // Variable to store the input character

    // Display a message to prompt the user to input a character
    printf("\n Check whether a character is digit or not :\n");
    printf("----------------------------------------------\n");
    printf(" Input a character : ");

    scanf("%c", &TestChar); // Read a character from user input

    // Check if the input character is a digit using isdigit() function
    if (isdigit(TestChar)) {
        printf(" The entered character is a digit. \n\n"); // Display message if it's a digit
    } else {
        printf(" The entered character is not a digit. \n\n"); // Display message if it's not a digit
    }

    return 0; // Return 0 to indicate successful execution of the program
}

Output:

 Check whether a character is digit or not :
----------------------------------------------
 Input a character : 8
 The entered character is a digit.

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C program to check if an input character is a digit by comparing its ASCII value without using isdigit().
• Write a C program to determine if a character is numeric and convert it to its integer equivalent.
• Write a C program to validate whether a character is a digit and print a corresponding message.
• Write a C program to test if a character is a digit and count its occurrences in a user-provided string.

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