C++ Programming Coding Questions and Answers PDF

C++ Programming Coding Questions and Answers PDF

C++ continues to be an essential programming language in 2025, forming the foundation of system programming, game development, and other high-performance computing applications. For those preparing for technical interviews or competitive programming, a strong grasp of C++ coding challenges remains indispensable. As of 10:55 PM IST on Sunday, October 5th, 2025, this resource presents eight sample C++ problems with solutions to initiate your preparation. Additionally, a downloadable PDF cheatsheet is available, containing a comprehensive collection of 50 questions accompanied by thorough solutions to facilitate skill development.

8 Example C++ Coding Questions and Answers

These examples cover fundamental to intermediate concepts in C++.

1. Fibonacci Series

Question: Print the Fibonacci series up to n terms.

#include <iostream>
using namespace std;

int main() {
    int n, t1 = 0, t2 = 1, nextTerm = 0;
    cout << "Enter the number of terms: ";
    cin >> n;
    for (int i = 1; i <= n; ++i) {
        if (i == 1) {
            cout << t1 << ", ";
            continue;
        }
        if (i == 2) {
            cout << t2 << ", ";
            continue;
        }
        nextTerm = t1 + t2;
        t1 = t2;
        t2 = nextTerm;
        cout << nextTerm << ", ";
    }
    return 0;
}

Explanation: Generates the series iteratively. Time Complexity: O(n).

2. Reverse a Number

Question: Reverse a given integer.

#include <iostream>
using namespace std;

int main() {
    int n, reversed = 0;
    cout << "Enter a number: ";
    cin >> n;
    while (n != 0) {
        int digit = n % 10;
        reversed = reversed * 10 + digit;
        n /= 10;
    }
    cout << "Reversed number: " << reversed;
    return 0;
}

Explanation: Extracts digits using modulo. Time Complexity: O(log n).

3. Check Prime Number

Question: Check if a number is prime.

#include <iostream>
#include <cmath>
using namespace std;

int main() {
    int n;
    cout << "Enter a number: ";
    cin >> n;
    bool isPrime = true;
    if (n <= 1) isPrime = false;
    else for (int i = 2; i <= sqrt(n); i++) if (n % i == 0) isPrime = false;
    if (isPrime) cout << n << " is prime.";
    else cout << n << " is not prime.";
    return 0;
}

Explanation: Checks divisibility up to sqrt(n). Time Complexity: O(sqrt(n)).

4. Largest Element in Array

Question: Find the largest element in an array.

#include <iostream>
using namespace std;

int main() {
    int n;
    cout << "Enter size: ";
    cin >> n;
    int arr[n];
    for (int i = 0; i < n; i++) cin >> arr[i];
    int max = arr[0];
    for (int i = 1; i < n; i++) if (arr[i] > max) max = arr[i];
    cout << "Largest: " << max;
    return 0;
}

Explanation: Tracks the maximum value. Time Complexity: O(n).

5. Factorial Using Recursion

Question: Calculate factorial using recursion.

#include <iostream>
using namespace std;

int factorial(int n) {
    if (n <= 1) return 1;
    return n * factorial(n - 1);
}

int main() {
    int n;
    cout << "Enter a number: ";
    cin >> n;
    if (n < 0) cout << "Invalid input.";
    else cout << "Factorial: " << factorial(n);
    return 0;
}

Explanation: Recursive function for factorial. Time Complexity: O(n).

6. Check Palindrome

Question: Check if a number is a palindrome.

#include <iostream>
using namespace std;

int main() {
    int n, original, reversed = 0;
    cout << "Enter a number: ";
    cin >> n;
    original = n;
    while (n != 0) {
        int digit = n % 10;
        reversed = reversed * 10 + digit;
        n /= 10;
    }
    if (original == reversed) cout << "Palindrome";
    else cout << "Not a palindrome";
    return 0;
}

Explanation: Compares original with reversed number. Time Complexity: O(log n).

7. Sum of Array Elements

Question: Calculate the sum of array elements.

#include <iostream>
using namespace std;

int main() {
    int n;
    cout << "Enter size: ";
    cin >> n;
    int arr[n];
    for (int i = 0; i < n; i++) cin >> arr[i];
    int sum = 0;
    for (int i = 0; i < n; i++) sum += arr[i];
    cout << "Sum: " << sum;
    return 0;
}

Explanation: Adds all elements iteratively. Time Complexity: O(n).

8. Swap Two Numbers

Question: Swap two numbers without a temporary variable.

#include <iostream>
using namespace std;

int main() {
    int a, b;
    cout << "Enter two numbers: ";
    cin >> a >> b;
    a = a + b;
    b = a - b;
    a = a - b;
    cout << "After swap: a = " << a << ", b = " << b;
    return 0;
}

Explanation: Uses arithmetic to swap values. Time Complexity: O(1).

Explore the Full List

These 8 questions are just a starting point! To master C++ for 2025 interviews and competitions, download the comprehensive PDF cheatsheet containing 50 C++ coding questions with detailed answers. Click here to get your copy and elevate your programming skills!

Why These Questions Matter in 2025

C++'s performance and low-level control make it critical for industries like gaming and embedded systems in 2025. These questions test essential skills like loops, recursion, and array manipulation, which are key in technical interviews and coding challenges.

Conclusion

Practice these 8 C++ coding questions and download the PDF with 50+ solutions to prepare for 2025 opportunities. Consistent practice will sharpen your problem-solving skills and boost your confidence in C++ programming!