Throwing exceptions in C++ - Mini Project: Build & Apply

Throwing exceptions

📖 Scenario: Imagine you are writing a simple program that checks if a number is positive. If the number is negative, the program should stop and show an error message.

🎯 Goal: You will create a program that throws an exception when a negative number is found and handles it gracefully.

📋 What You'll Learn

Create an integer variable named number with the value -5

Create a boolean variable named checkPositive and set it to true

Use a try block to check if number is negative and throw an exception with the message "Negative number found"

Use a catch block to catch the exception and print the exception message

💡 Why This Matters

🌍 Real World

Throwing exceptions helps programs stop when something goes wrong, like invalid input or unexpected situations.

💼 Career

Understanding exceptions is important for writing safe and reliable C++ programs in software development jobs.

1

Create the number variable

Create an integer variable called number and set it to -5.

C++

# Create an integer variable called number and set it to -5
# Your code here

Need a hint?

Use int number = -5; to create the variable.

2

Create the checkPositive variable

Create a boolean variable called checkPositive and set it to true.

C++

int number = -5;
# Create a boolean variable called checkPositive and set it to true
# Your code here

Need a hint?

Use bool checkPositive = true; to create the variable.

3

Add a try block to throw an exception

Write a try block that checks if number is less than 0. If yes, throw a std::runtime_error exception with the message "Negative number found".

C++

int number = -5;
bool checkPositive = true;

// Add a try block to check number and throw exception if negative
# Your code here

Need a hint?

Use try { if (number < 0) throw std::runtime_error("Negative number found"); }.

4

Add a catch block to handle the exception and print the message

Add a catch block that catches std::runtime_error exceptions by reference as e and prints e.what() using std::cout.

C++

int number = -5;
bool checkPositive = true;

try {
    if (number < 0) {
        throw std::runtime_error("Negative number found");
    }
}
// Add a catch block to handle the exception and print the message
# Your code here

Need a hint?

Use catch (const std::runtime_error& e) { std::cout << e.what() << std::endl; }.