Difference between revisions of "Advanced-C++/C2/Exception-Handling/English"

Learning Objectives

Exception Handling.

We will do this with the help of an example.

System requirements

Ubuntu OS version 11.10

g++ compiler v. 4.6.1

Introduction to Exception

An exception is a problem that arises during the execution of a program

It is a run-time error that a program may detect

Introduction to Exception Handling

The response given to the problems occured during the execution of the program is known as exception handling.

Exception handling allows a program to continue execution.

Helps Identifying the problem.

Terminates the program in a controlled manner.

Types of Exceptions

Try

Catch

Throw

We place the error prone code inside a try block

Then it is Handled using throw.

after this the exception is caught, using catch statement

And then it is processed.

Syntax

Throw:

try {

// try block

}

catch (type1 arg) {

// catch block

}

catch (type2 arg) {

// catch block

}

The try block and the catch block, here we pass argument

The throw statement can be written inside the try block as well

We can have more than try, catch blocks.

I have the code, i will explain it to you.

In this program we will solve the divide by zero error using exception handling.

Let us go through the code

#include <iostream>

using namespace std;

Here we are using the std namespace.

double division(int a, int b)

{

if( b == 0 )

{

throw "Division by zero condition!";

}

return (a/b);

}

We check whether b ==0.

If true, we throw an exception division by zero condition

The function returns division of a and b

int main()

int x,y;

double z;

cout<<"Enter value of x and y\n";

cin>>x>>y;

Here we accept the values of x and y.

try

{

z = division(x, y);

cout << z<<"\n";

}

Here we have called the function division.

And stored the result in z.

Then we print the value of z.

catch (const char* msg)

{

In this we pass an argument msg as a character constant.

cout << msg << endl;

}

return 0;

Ctrl, Alt and T keys simultaneously

g++ exception.cpp -o exp

To execute

Type

./exp

g++ exception.cpp -o ex

To execute

Type

./ex

Output

Enter the value of x and y:

I will first enter as 3 and 0

The output is displayed as:

Division by zero condition

Let us compile again

Press the up arrow key twice

Press enter, again press the up arrow key twice

Enter value of x and y

i will give as 8 and 2

The output is 4

Let us come back to our slides

Summary

Exception Handling

Try

Catch

Throw blocks

Assignment

Display the age of employess.

Throw an exception to check that the age is not less than 15.

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Acknowledgement

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