The Try-Catch Block

In C++, exceptions are a way to handle errors that occur during the execution of a program. When an exception is thrown, the program stops executing the current code and starts looking for a piece of code that can handle the exception.

The try-catch block is used to catch and handle exceptions in C++. Here's how it works:

• The try block contains the code that may throw an exception. This is where you would include the code that you want to monitor for errors.
• The catch block is used to catch and handle the exception. It specifies the type of exception that it can handle and includes the code to be executed when that type of exception is caught.

Here's an example of a try-catch block in C++:

1#include <iostream>
2
3using namespace std;
4
5int main() {
6    try {
7        // code that may throw an exception
8    }
9    catch (exception& e) {
10        // code to handle the exception
11    }
12    return 0;
13}

In this example, the try block contains the code that may throw an exception. If an exception of type exception is thrown, the catch block will be executed to handle the exception.

When an exception is caught, you have the opportunity to handle it in some way. You can display an error message, log the exception, or take any other action that you deem appropriate.

The catch block can also handle multiple types of exceptions by using multiple catch blocks.

It's important to note that the catch block must have the same type (or a base class type) as the exception being thrown. If the exception does not match any of the catch blocks, it will not be caught and the program will terminate.

Using try-catch blocks allows you to control the flow of your program when exceptions occur. Instead of the program crashing and displaying an error message to the user, you can gracefully handle the exception and continue execution or take appropriate action.

Keep in mind that exceptions should be used for exceptional circumstances, such as when something unexpected happens or when an error occurs that cannot be easily handled locally. They should not be used for normal control flow within your program.

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#include <iostream>

​

using namespace std;

​

int main() {

    try {

        // code that may throw an exception

    }

    catch (exception& e) {

        // code to handle the exception

    }

    return 0;

}

Throwing Exceptions

In C++, exceptions are a way to handle errors that occur during the execution of a program. Exceptions provide a mechanism for the program to transfer control to a specific block of code when an error occurs.

When you encounter a situation in your code where an error occurs or an unexpected condition arises, you can throw an exception using the throw keyword. Throwing an exception allows you to pass control to an appropriate handler elsewhere in your code.

Here's an example of throwing an exception in C++:

1#include <iostream>
2
3using namespace std;
4
5int divide(int a, int b) {
6    if (b == 0) {
7        throw exception();
8    }
9    return a / b;
10}
11
12int main() {
13    try {
14        int result = divide(10, 0);
15        cout << "Result: " << result << endl;
16    }
17    catch (exception& e) {
18        cout << "Exception Caught!" << endl;
19    }
20    return 0;
21}

In this example, the divide function throws an exception when the second parameter, b, is equal to 0. The exception is caught in the catch block and an error message is displayed.

Throwing exceptions allows you to handle error conditions gracefully and provides a way to communicate error information between different parts of your code.

When choosing which exceptions to throw, consider the specific error scenario and the appropriate action to take when the exception is caught. You can also create custom exception classes to represent different types of errors and handle them accordingly.

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#include <iostream>

using namespace std;

​

int main() {

  // replace with your c++ logic here

}

In C++, exception handling allows you to catch and handle errors that occur during the execution of a program. While C++ provides built-in exception classes such as std::exception, you can also create your own custom exception classes to handle specific error scenarios.

Creating custom exception classes allows you to provide more specific information about the error and define custom behavior for handling it. This can be especially useful when you want to differentiate between different types of errors or when you want to add additional properties or methods to your exception class.

To create a custom exception class in C++, you can follow these steps:

1. Define a new class that inherits from the std::exception class or one of its derived classes.
2. Implement any additional properties or methods that you want to include in your custom exception class.
3. Override the what() method to provide a human-readable error message.

Here's an example of creating a custom exception class in C++:

1#include <iostream>
2#include <exception>
3
4class CustomException : public std::exception {
5public:
6    const char* what() const noexcept override {
7        return "This is a custom exception.";
8    }
9};
10
11int main() {
12    try {
13        throw CustomException();
14    }
15    catch (const std::exception& e) {
16        std::cout << "Exception caught: " << e.what() << std::endl;
17    }
18    return 0;
19}

In this example, we define a custom exception class CustomException that inherits from the std::exception class. We override the what() method to provide a custom error message. Inside the main() function, we throw an instance of CustomException and catch it using a std::exception reference. The what() method is called to retrieve the error message and display it.

By creating custom exception classes, you can have more fine-grained control over the handling of different types of errors in your C++ programs. This can help you handle errors in a more specific and meaningful way, improving the overall quality and maintainability of your code.

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#include <iostream>

#include <exception>

​

class CustomException : public std::exception {

public:

    const char* what() const noexcept override {

        return "This is a custom exception.";

    }

};

​

int main() {

    try {

        throw CustomException();

    }

    catch (const std::exception& e) {

        std::cout << "Exception caught: " << e.what() << std::endl;

    }

    return 0;

}