Check if Number Is Positive or Negative

Introduction

In this lab, we will learn how to determine if a user-entered number is positive or negative using C++ programming language. We will achieve this by using the concept of if-else blocks.

Write the starting code

In the newly created main.cpp file,

#include <iostream>
using namespace std;

int main()
{
    cout << "\n\nWelcome to this C++ program! \n\n";

    return 0;
}

This will import the necessary libraries and print the welcome message.

Prompt the user to Enter a Number

#include <iostream>
using namespace std;

int main()
{
    cout << "\n\nWelcome to this C++ program! \n\n";

    int num;
    cout << "Enter a non-zero numeric value: ";
    cin >> num;

    return 0;
}

Here, we prompt the user to input a non-zero numeric value using the cin statement and store the value in num.

Implement the if-else Block to Determine if the Number is Positive or Negative

#include <iostream>
using namespace std;

int main()
{
    cout << "\n\nWelcome to this C++ program! \n\n";

    int num;
    cout << "Enter a non-zero numeric value: ";
    cin >> num;

    if (num > 0) {
        cout << num << " is a positive number." << endl;
    } else {
        cout << num << " is a negative number." << endl;
    }

    return 0;
}

In this step, we create an if-else block to compare num with 0. If num is greater than 0, it is a positive number; else, it is a negative number.

Compile and Run the Program

Open the terminal in Ubuntu system, navigate to the directory where the main.cpp file is located, and use the following command to compile and run the program:

$ g++ main.cpp -o main && ./main

Summary

In this lab, we learned how to determine if a user-entered number is positive or negative using C++ programming language. We achieved this by using the concept of if-else blocks.