C Interview Programs

Definition and Usage

C interview programs are short practice problems used in C tutorials, college labs, and fresher technical rounds. They reward clear loops, careful conditions, and clean stdio I/O more than large application design.

What you practice

Most drills build the same C skills: read input, process with for/while and if, print results, and handle edge cases. Number checks, digit math, arrays, matrices, and base conversions show up again and again.

What should beginners solve first?

Start with Even Number, Odd Number, and Prime Number. Then try Sum of Digits, Factorial, and Fibonacci Series before arrays and matrices.

This lesson vs program pages

This page is the C interview hub: how to approach problems, which topic to practice next, and how each tutorial is structured. The programs index lists 50 individual guides—each with algorithm, complete code, output, and FAQs.

C Syntax

A typical interview program reads a value, decides with a condition or loop, and prints the result:

#include <stdio.h>

int main(void) {
    int n;

    printf("Enter a number: ");
    if (scanf("%d", &n) != 1) {
        return 1;
    }

    if (n % 2 == 0) {
        printf("%d is even.\n", n);
    } else {
        printf("%d is odd.\n", n);
    }

    return 0;
}
/* gcc interview_skeleton.c -std=c11 -o interview_skeleton */

Core C Concepts

Skills these C interview programs reinforce:

Learning order in this C tutorial

Choose a Topic by Goal

Pick a practice cluster based on what you need to strengthen:

Jump to a category

How to Practice Interview Programs in C

A practical workflow for this tutorial track:

1. Read the problem: inputs, outputs, and constraints (range, negatives, zero).
2. Write the algorithm in plain language before coding.
3. Implement with #include <stdio.h>, clear variable names, and checked scanf.
4. Test edge cases, then compile: gcc file.c -std=c11 -o out.
5. Explain time complexity in one sentence (often O(1) or O(n) for these drills).
6. Open the next program in the same category before jumping topics.

Live Preview

Enter an integer to preview the even/odd check—the same idea as Even Number and Odd Number.

C Examples

Three starter patterns from this C tutorial track. Open the linked program page for the full walkthrough.

#include <stdio.h>

int main(void) {
    int n = 18;

    if (n % 2 == 0) {
        printf("%d is even.\n", n);
    } else {
        printf("%d is odd.\n", n);
    }

    return 0;
}

18 is even.

#include <stdio.h>

int main(void) {
    int n = 482;
    int sum = 0;
    int temp = n;

    while (temp > 0) {
        sum += temp % 10;
        temp /= 10;
    }

    printf("Sum of digits of %d = %d\n", n, sum);
    return 0;
}

Sum of digits of 482 = 14

#include <stdio.h>

int main(void) {
    int nums[] = { 4, 7, 1, 9 };
    int n = (int)(sizeof nums / sizeof nums[0]);
    int i;
    int sum = 0;

    for (i = 0; i < n; i++) {
        sum += nums[i];
    }

    printf("Sum = %d\n", sum);
    return 0;
}

Sum = 21

C Interview Programs Index

50 practice programs. Search by name or browse by category. Each row opens a full C tutorial.

Key Takeaways