C++ - Practice Exercise

Practice Questions for C++

Introduction

This document provides notes for 10 C++ practice questions that will help you enhance your understanding of various concepts in C++. Each question is followed by an explanation and key concepts that are tested in the exercise.

Questions

1. Write a program to print "Hello, World!"

This basic exercise introduces you to the structure of a C++ program, the syntax, and how to print output using std::cout.

#include 
using namespace std;

int main() {
    cout << "Hello, World!" << endl;
    return 0;
}
    

2. Program to find the largest of three numbers

This exercise teaches how to use conditional statements (if-else) to compare multiple values and find the largest number.

#include 
using namespace std;

int main() {
    int a, b, c;
    cout << "Enter three numbers: ";
    cin >> a >> b >> c;

    if (a >= b && a >= c)
        cout << "Largest number is " << a << endl;
    else if (b >= a && b >= c)
        cout << "Largest number is " << b << endl;
    else
        cout << "Largest number is " << c << endl;

    return 0;
}
    

3. Program to check if a number is prime

This question helps you practice loops and conditional logic to determine whether a given number is prime or not.

#include 
using namespace std;

bool isPrime(int n) {
    if (n <= 1) return false;
    for (int i = 2; i <= n / 2; i++) {
        if (n % i == 0)
            return false;
    }
    return true;
}

int main() {
    int num;
    cout << "Enter a number: ";
    cin >> num;
    
    if (isPrime(num))
        cout << num << " is a prime number." << endl;
    else
        cout << num << " is not a prime number." << endl;

    return 0;
}
    

4. Program to calculate the factorial of a number

This exercise teaches you how to use loops or recursion to calculate the factorial of a given number.

#include 
using namespace std;

int factorial(int n) {
    int result = 1;
    for (int i = 1; i <= n; i++) {
        result *= i;
    }
    return result;
}

int main() {
    int num;
    cout << "Enter a number: ";
    cin >> num;
    cout << "Factorial of " << num << " is " << factorial(num) << endl;
    return 0;
}
    

5. Program to reverse a number

This exercise helps you practice using loops and arithmetic operations to reverse a given number.

#include 
using namespace std;

int reverse(int n) {
    int rev = 0;
    while (n > 0) {
        rev = rev * 10 + n % 10;
        n /= 10;
    }
    return rev;
}

int main() {
    int num;
    cout << "Enter a number: ";
    cin >> num;
    cout << "Reversed number is " << reverse(num) << endl;
    return 0;
}
    

6. Program to find the Fibonacci sequence up to a certain number

This question teaches you how to implement the Fibonacci sequence using loops or recursion.

#include 
using namespace std;

void fibonacci(int n) {
    int a = 0, b = 1, c;
    cout << "Fibonacci sequence up to " << n << ": ";
    for (int i = 0; i < n; i++) {
        cout << a << " ";
        c = a + b;
        a = b;
        b = c;
    }
    cout << endl;
}

int main() {
    int num;
    cout << "Enter the number of terms: ";
    cin >> num;
    fibonacci(num);
    return 0;
}
    

7. Program to find the sum of digits of a number

This exercise involves using arithmetic operations and loops to find the sum of digits of a number.

#include 
using namespace std;

int sumOfDigits(int n) {
    int sum = 0;
    while (n > 0) {
        sum += n % 10;
        n /= 10;
    }
    return sum;
}

int main() {
    int num;
    cout << "Enter a number: ";
    cin >> num;
    cout << "Sum of digits: " << sumOfDigits(num) << endl;
    return 0;
}
    

8. Program to check if a number is Armstrong

This problem teaches you how to implement the logic to check if a given number is an Armstrong number.

#include 
#include 
using namespace std;

bool isArmstrong(int n) {
    int sum = 0, temp, remainder, digits = 0;
    temp = n;
    
    while (temp != 0) {
        temp /= 10;
        digits++;
    }
    
    temp = n;
    while (temp != 0) {
        remainder = temp % 10;
        sum += pow(remainder, digits);
        temp /= 10;
    }

    return (sum == n);
}

int main() {
    int num;
    cout << "Enter a number: ";
    cin >> num;
    
    if (isArmstrong(num))
        cout << num << " is an Armstrong number." << endl;
    else
        cout << num << " is not an Armstrong number." << endl;

    return 0;
}
    

9. Program to check if a number is even or odd

This simple exercise helps you practice using the modulus operator to check if a number is even or odd.

#include 
using namespace std;

int main() {
    int num;
    cout << "Enter a number: ";
    cin >> num;
    
    if (num % 2 == 0)
        cout << num << " is even." << endl;
    else
        cout << num << " is odd." << endl;

    return 0;
}
    

10. Program to calculate the area of a circle

This exercise teaches you how to calculate the area of a circle given the radius using the formula Area = π * r * r.

#include 
#include 
using namespace std;

int main() {
    double radius, area;
    cout << "Enter the radius of the circle: ";
    cin >> radius;

    area = M_PI * radius * radius;  // M_PI is a constant from cmath
    cout << "Area of the circle is: " << area << endl;

    return 0;
}
    

These 10 C++ practice questions cover a range of basic programming concepts, including loops, conditionals, functions, and arithmetic operations. Solving these questions will help you build a solid foundation in C++ programming.