Handling Exceptions with Try-Catch in C++

Tutorial 1 of 5

1. Introduction

In this tutorial, we will cover exception handling in C++ using try and catch blocks. Exception handling is a mechanism that separates code that detects and handles exceptional circumstances from the rest of your program. This is very important in producing robust and error-free code.

After completing this tutorial, you should be able to understand how to anticipate and handle potential errors in your code with the try and catch blocks in C++.

Prerequisites:
- Basic knowledge of C++ programming
- Understanding of C++ control structures

2. Step-by-Step Guide

In C++, exception handling is accomplished with the try, catch, and throw keywords.

  • Try: Encloses the code that may potentially result in an error.
  • Throw: Throws an exception when an error occurs.
  • Catch: Captures and handles the exception thrown.

Here are the steps to use try and catch blocks:

  1. Enclose the code that might throw an exception in a try block.
  2. Use a throw statement to throw an exception if a problem is detected.
  3. Handle the exception using a catch block.

Best Practice:
- Always keep the try block as short as possible and only include statements that might throw exceptions.
- Have separate catch blocks for different types of exceptions to handle them differently.

3. Code Examples

Example 1: Basic Try-Catch

try {
    // Code that could throw an exception
    throw "This is an exception!";
} catch(const char* e) {
    // Handle the exception
    std::cout << "Caught an exception: " << e << std::endl;
}

In this example, we throw a string exception and catch it in the catch block. The output will be Caught an exception: This is an exception!.

Example 2: Multiple Catch Blocks

try {
    // Code that could throw an exception
    throw 10;
} catch(int e) {
    // Handle the exception
    std::cout << "Caught an integer exception: " << e << std::endl;
} catch(const char* e) {
    // Handle the exception
    std::cout << "Caught a string exception: " << e << std::endl;
}

Here, we throw an integer exception and have two catch blocks. The first catch block catches integer exceptions and the second catch block catches string exceptions. The output will be Caught an integer exception: 10.

4. Summary

We have covered how to handle exceptions in C++ using try and catch blocks. We learned how to anticipate and handle potential errors in our code.

Next, you should practice using try and catch with different types of exceptions. The more you practice, the more you'll understand how to handle exceptions.

5. Practice Exercises

Exercise 1: Write a program that throws a string exception if a number is less than 10.

Solution:

int number = 5;
try {
    if(number < 10) {
        throw "Number is less than 10!";
    }
} catch(const char* e) {
    std::cout << "Caught an exception: " << e << std::endl;
}

Exercise 2: Write a program that throws an integer exception if the division of two numbers is not a whole number.

Solution:

int num1 = 10;
int num2 = 3;
try {
    if(num1 % num2 != 0) {
        throw num1 / num2;
    }
} catch(int e) {
    std::cout << "Caught an exception: " << e << std::endl;
}

Tips for further practice:
- Try using multiple catch blocks with different types of exceptions.
- Throw exceptions from within functions and catch them in the calling function.