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Introduction to Exceptions in C++

When you write C++ programs, unexpected situations can occur during execution. These situations are called exceptions. Exceptions might arise when your code tries to divide by zero, open a file that does not exist, or access out-of-range elements in an array. Handling such cases is crucial for building robust, reliable software.

Traditionally, programmers have used error codes to signal problems. However, error codes have several drawbacks:

They can be ignored accidentally;
They require you to check the return value after every operation;
They make code harder to read and maintain.

C++ introduces a structured way to handle errors using exception handling. This mechanism separates the normal flow of your code from error-handling logic, making programs clearer and more maintainable.

main.cpp


              12345678910111213
            
#include <iostream>

int main() {
    try {
        std::cout << "About to throw an exception..." << std::endl;
        throw 42;
        std::cout << "This line will not execute." << std::endl;
    } catch (int e) {
        std::cout << "Caught exception: " << e << std::endl;
    }
    std::cout << "Program continues after catch block." << std::endl;
    return 0;
}

Understanding `try`, `throw`, and `catch`

The code above demonstrates the three main keywords used in C++ exception handling: try, throw, and catch.

The try block contains code that might produce an exception. If everything runs smoothly, the code continues as normal;
The throw statement signals that something unexpected has happened. In this case, the integer 42 is thrown as an exception;
The catch block handles the exception. It only executes if an exception of the specified type is thrown inside the preceding try block. Here, the value 42 is caught as an integer and printed.

Once an exception is thrown, the rest of the code in the try block is skipped, and control transfers to the appropriate catch block. After the catch block finishes, execution continues after the entire try-catch structure.

1. Which statement best describes the purpose of a try-catch block in C++?

2. What happens if an exception is thrown but not caught by any catch block?

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Introduction to Exceptions in C++

Traditionally, programmers have used error codes to signal problems. However, error codes have several drawbacks:

They can be ignored accidentally;
They require you to check the return value after every operation;
They make code harder to read and maintain.

main.cpp


              12345678910111213
            
#include <iostream>

int main() {
    try {
        std::cout << "About to throw an exception..." << std::endl;
        throw 42;
        std::cout << "This line will not execute." << std::endl;
    } catch (int e) {
        std::cout << "Caught exception: " << e << std::endl;
    }
    std::cout << "Program continues after catch block." << std::endl;
    return 0;
}

Understanding `try`, `throw`, and `catch`

The code above demonstrates the three main keywords used in C++ exception handling: try, throw, and catch.

The try block contains code that might produce an exception. If everything runs smoothly, the code continues as normal;
The throw statement signals that something unexpected has happened. In this case, the integer 42 is thrown as an exception;
The catch block handles the exception. It only executes if an exception of the specified type is thrown inside the preceding try block. Here, the value 42 is caught as an integer and printed.

1. Which statement best describes the purpose of a try-catch block in C++?

2. What happens if an exception is thrown but not caught by any catch block?

Var alt klart?

Tak for dine kommentarer!

Sektion 1. Kapitel 1

Understanding Exception Handling

Introduction to Exceptions in C++

Understanding try, throw, and catch

1. Which statement best describes the purpose of a try-catch block in C++?

2. What happens if an exception is thrown but not caught by any catch block?

Awesome!

Understanding Exception Handling

Introduction to Exceptions in C++

Understanding try, throw, and catch

1. Which statement best describes the purpose of a try-catch block in C++?

2. What happens if an exception is thrown but not caught by any catch block?

Understanding `try`, `throw`, and `catch`

Understanding `try`, `throw`, and `catch`