C PROGRAMMING PROGRAM • STRINGS

Count Vowels, Consonants, Digits and Spaces

Learn how to count vowels, consonants, digits and spaces using a clear C program.

Beginnerctype.hCharacter classesCounters

PROBLEM UNDERSTANDING

Input and expected output

Sample input

C is fun 2026

Sample output

Vowels = 2
Consonants = 4
Digits = 4
Spaces = 3

COMPLETE C PROGRAM

Complete C implementation

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

int main(void)
{
    char text[300];
    int vowels = 0, consonants = 0, digits = 0, spaces = 0;

    fgets(text, sizeof text, stdin);
    for (int index = 0; text[index] != '\0'; index++) {
        unsigned char value = (unsigned char) text[index];
        if (isdigit(value)) digits++;
        else if (isspace(value)) { if (value != '\n') spaces++; }
        else if (isalpha(value)) {
            char lower = (char) tolower(value);
            if (lower == 'a' || lower == 'e' || lower == 'i' || lower == 'o' || lower == 'u') vowels++;
            else consonants++;
        }
    }
    printf("Vowels = %d\nConsonants = %d\nDigits = %d\nSpaces = %d\n", vowels, consonants, digits, spaces);
    return 0;
}

CURRENT STEP

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EXPECTED OUTPUT FOR THE SAMPLE

Vowels = 2
Consonants = 4
Digits = 4
Spaces = 3

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Classify each character with ctype functions and update the matching counter.
Display the computed result.

Classify each character with ctype functions and update the matching counter.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

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.