C PROGRAMMING PROGRAM • DECISION MAKING

Identify an Alphabet, Digit or Special Character

Learn how to identify an alphabet, digit or special character using a clear C program.

Beginnerctype.hisalpha()isdigit()

PROBLEM UNDERSTANDING

Input and expected output

Sample input

Sample output

Special character

COMPLETE C PROGRAM

Complete C implementation

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

int main(void)
{
    char character;

    printf("Enter a character: ");
    scanf(" %c", &character);
    if (isalpha((unsigned char) character))
        printf("Alphabet\n");
    else if (isdigit((unsigned char) character))
        printf("Digit\n");
    else
        printf("Special character\n");
    return 0;
}

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

No line selected

EXPECTED OUTPUT FOR THE SAMPLE

Special character

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Use standard character-classification functions before treating the remaining input as special.
Display the computed result.

Use standard character-classification functions before treating the remaining input as special.

EFFICIENCY

Time and space complexity

Time complexity

O(1)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

Check this

Use the correct format specifier for every variable.

Check this

Initialize variables before using their values.

Check this

Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.