C++ Basic Programs With Solutions

7 min read Jul 01, 2024

C++ Basic Programs with Solutions

This article will guide you through some basic C++ programs with solutions. These programs will help you understand fundamental concepts in C++ programming.

1. Hello World!

The classic first program in any programming language is "Hello World!". This simple program displays the message "Hello World!" on the screen.

Code:

#include 

using namespace std;

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

Explanation:

#include <iostream>: This line includes the iostream library, which provides input/output functionalities.
using namespace std;: This line brings the standard namespace into scope, allowing us to use elements like cout and endl without explicitly specifying std::.
int main(): This is the main function, where the program execution starts.
cout << "Hello World!" << endl;: This line prints the message "Hello World!" to the console. cout is the standard output stream, << is the insertion operator used to send data to the output stream, and endl inserts a newline character at the end of the output.
return 0;: This statement returns 0, indicating successful program execution.

2. Addition of Two Numbers

This program takes two numbers as input from the user and displays their sum.

Code:

#include 

using namespace std;

int main() {
  int num1, num2, sum;

  cout << "Enter the first number: ";
  cin >> num1;

  cout << "Enter the second number: ";
  cin >> num2;

  sum = num1 + num2;

  cout << "Sum = " << sum << endl;

  return 0;
}

Explanation:

int num1, num2, sum;: This line declares three integer variables to store the two input numbers and their sum.
cin >> num1;: This line takes the first number from the user and stores it in the variable num1. cin is the standard input stream, and >> is the extraction operator used to read data from the input stream.
sum = num1 + num2;: This line calculates the sum of the two numbers and stores it in the variable sum.
cout << "Sum = " << sum << endl;: This line displays the calculated sum on the console.

3. Finding the Largest Number

This program takes two numbers as input from the user and displays the largest number.

Code:

#include 

using namespace std;

int main() {
  int num1, num2, largest;

  cout << "Enter the first number: ";
  cin >> num1;

  cout << "Enter the second number: ";
  cin >> num2;

  if (num1 > num2) {
    largest = num1;
  } else {
    largest = num2;
  }

  cout << "Largest number = " << largest << endl;

  return 0;
}

Explanation:

if (num1 > num2) { ... } else { ... }: This conditional statement checks if the first number is greater than the second number. If it is, the largest variable is assigned the value of num1. Otherwise, largest is assigned the value of num2.

4. Factorial of a Number

This program takes a positive integer as input and calculates its factorial.

Code:

#include 

using namespace std;

int main() {
  int num, factorial = 1;

  cout << "Enter a positive integer: ";
  cin >> num;

  for (int i = 1; i <= num; ++i) {
    factorial *= i;
  }

  cout << "Factorial of " << num << " = " << factorial << endl;

  return 0;
}

Explanation:

for (int i = 1; i <= num; ++i) { ... }: This loop iterates from 1 to the input number.
factorial *= i;: In each iteration, the factorial variable is multiplied by the current loop counter i.

5. Checking Prime Number

This program takes a positive integer as input and checks if it is a prime number.

Code:

#include 

using namespace std;

int main() {
  int num, i, isPrime = 1;

  cout << "Enter a positive integer: ";
  cin >> num;

  for (i = 2; i <= num / 2; ++i) {
    if (num % i == 0) {
      isPrime = 0;
      break;
    }
  }

  if (isPrime == 1) {
    cout << num << " is a prime number." << endl;
  } else {
    cout << num << " is not a prime number." << endl;
  }

  return 0;
}

Explanation:

for (i = 2; i <= num / 2; ++i) { ... }: This loop iterates from 2 to half of the input number.
if (num % i == 0) { ... }: This condition checks if the input number is divisible by the current loop counter i. If it is, the number is not prime, and the isPrime flag is set to 0.
break;: This statement exits the loop if the number is not prime.

These basic C++ programs provide a good starting point for learning the language. As you progress, you can explore more complex programs and concepts.

C++ Basic Programs With Solutions