What is exception handling in C++ ?

• In C++ exception handling is a process to handle runtime errors.
• If we perform exception handling, so the normal flow of the application can be maintained even after runtime errors.
• At run time exception is an event or object which is thrown in C++ and all exceptions are derived from std::exception class.
• It prints exception message and terminates the program, if we don’t handle the exception.
• In C++ exception handling consists of three keywords, they are try, throw, catch
• In exception handling try keyword allows you to define a block of code to be tested for errors when it is being executed.
• In exception handling throw keyword throws an exception when a problem is detected, which lets us create a custom error.
• In exception handling catch keyword allows you to define a block of code to be executed, if an error occurs in the try block.

Syntax

             try {
  // Block of code to try
  throw exception; // Throw an exception when a problem arise
}
catch () {
  // Block of code to handle errors
} 

Sample Code

try {
  int age = 15;
  if (age >= 18) {
    cout << "Access granted - you are old enough.";
  } else {
    throw (age);
  }
}
catch (int myNum) {
  cout << "Access denied - You must be at least 18 years old.\n";
  cout << "Age is: " << myNum;
}

Output