Exception Handling in C++

In C++, an exception is a situation that arises during the execution of a program code. In C++ program, an exception is a response to an exceptional situation that arises while a program is running, such as an attempt to divide by zero. Exceptions provide a way to transfer control from one part of a program to another part of the same program. Exception handling is built upon three keywords: try, throw and catch.

1. try: A try block in a program code, identifies that which particular exceptions will be activated and it followed by one or more catch blocks.

2. throw: A program code in C++, throws an exception when a problem shows up. This is done using a throw keyword.

3. catch: A program code in C++ catches an exception with an exception handler at the place in a program where you want to handle the problem. The catch keyword in the program code indicates the catching of an exception.

Assuming a block in C++ program code that will raise an exception, a method catches an exception using a combination of the try and catch keywords. A try/catch block is placed around the code that might generate an exception. Code within a try/catch block is referred to as protected code, and the syntax for using try/catch as follows: 

Syntex of the try/catch block:

try 

{

   // write your program code here

   // throw an exception 

} 

catch( ExceptionName a ) 

{

   // catch block program code

} 

catch( ExceptionName b ) 

{

   // catch block program code

} 

catch( ExceptionName c ) 

{

   // catch block program code

}

Program example on exception handling:

Programa 1:

Write a program in C++, which implement try/catch block.

#include<iostream>

using namespace std;

int main()

{

    int c= 11;

    try 

    {

        throw c;

    }

    catch(int a) 

    {

        cout << "An exception occurred!" << endl;

        cout << "Exception number is: " << a << endl;

    }

}

Output:

An exception occurred!

Exception number is: 11

Program example 2:

Write a program in C++, which implement try/catch block by implementing an error in try block and that particular exception is handled by the catch block.

#include<iostream>

using namespace std;

double division(int var1, int var2)

{

    if (var2 == 0) 

    {

        throw "Division by Zero.";

    }

    return (var1 / var2);

}

int main()

{

    int x = 10;

    int y = 0;

    float z = 0;

    try 

    {

        z = division(x, y);

        cout << z << endl;

    }

    catch (const char* abc) 

    {

        cout << abc << endl;

    }

    return 0;

}

Output:

Division by Zero.