Exception handling in C++

C++ exception handling is a mechanism that allows you to handle errors that occur during the execution of a program. It is built on three keywords: try, catch, and throw.

• The try keyword is used to define a block of code that can throw an exception.
• The catch keyword is used to define a block of code that is executed when a particular exception is thrown.
• The throw keyword is used to throw an exception.

The following is an example of a simple try-catch block:

int main() {
  try {
    // This code might throw an exception.
    throw(something can be of any type)
  } catch (int e) {
    // This code is executed if an exception of type int is thrown.
    std::cout << "An integer exception was thrown: " << e << std::endl;
  } catch (std::string e) {
    // This code is executed if an exception of type std::string is thrown.
    std::cout << "A string exception was thrown: " << e << std::endl;
  }
}

In this example, the try block contains the code that might throw an exception. The catch blocks are executed if a particular type of exception is thrown. In this case, there are two catch blocks: one for exceptions of type int and one for exceptions of type std::string.

If an exception is thrown in the try block, the first catch block that matches the type of the exception is executed. If no catch block matches the type of the exception, the program terminates abnormally.

You can also have multiple catch blocks for the same type of exception. In this case, the catch blocks are executed in the order in which they appear in the code.

The throw keyword is used to throw an exception. The syntax for the throw keyword is:

throw expression;

The expression can be any value. When the throw keyword is executed, the expression is passed to the first catch block that matches its type.

Here is an example of a throw statement:

throw 10;

This statement throws an exception of type int with the value of 10.

The try, catch, and throw keywords can be used to handle a wide variety of errors. For example, you can use them to handle errors that occur when opening files, reading from files, or writing to files. You can also use them to handle errors that occur when dividing by zero, accessing invalid memory, or calling a function that does not exist.