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So far, we have only seen one catch block associated with a try block. But it is also possible to have multiple catch blocks associated with one try block.

Why multiply blocks are useful?

Multiple catch blocks are used when we have to catch a specific type of exception out of many possible type of exceptions i.e. an exception of type char or int or short or long etc. Let's see the use of multiple catch blocks with an example.

Multiple Catch Block Example

#include<iostream>

using namespace std;

int main()
{
int a=10, b=0, c;
try
{
	//if a is divided by b(which has a value 0);
	if(b==0)
		throw(c); 
	else
	c=a/b; 		
		
}
catch(char c)     //catch block to handle/catch exception
{
	cout<<"Caught exception : char type ";
}
catch(int i)     //catch block to handle/catch exception
{
	cout<<"Caught exception : int type ";
}
catch(short s)     //catch block to handle/catch exception
{
	cout<<"Caught exception : short type ";
}
cout<<"\n Hello";
}

Output is -:

Caught exception : int type
 Hello

In this code, we have three catch blocks associated with one try block. At the runtime, compiler finds a division-by-zero problem, hence an exception of type int is thrown when a statement enclosed within the try block is executed.

This exception type is matched with the declared exception type in every catch-block(matching starts with the first catch block).


The catch block that matches with type of exception thrown is executed, while the rest of catch blocks are skipped. Let's see how -

• The first catch block has declared an exception of type char, which doesn't match with the exception int thrown by the try block, hence this catch-block is not executed.


• The second catch block declared with an int matches with the exception int thrown by the try block and hence second catch block will be executed.


• As, we have already found the matching catch block, hence, the third catch block with declared exception of type short is skipped, not checked and not executed.

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A catch block for all types exceptions

We could declare a catch block which catches all types of exceptions, irrespective of their types. In such catch block, instead of declaring the type of exception it can catch, we are going to use three dots(...) within its parenthesis. Let's see an example.

Let's understand this by an example -

#include<iostream>

using namespace std;

int main()
{
int a=10, b=0, c;
try
{
	//if a is divided by b(which has a value 0);
	if(b==0)
		throw(c); 
	else
	c=a/b; 		
		
}
catch(...)     //catch block to handle/catch exception
{
	cout<<"A catch block for all types of exceptions has caught an exception";
}

}

Output

A catch block for all types of exceptions has caught an exception

As you may see in the code above, a single catch block defined with three dots (...) has caught all types of exceptions i.e. an exception of type int, without even declaring it.





Another example


Let us see another example to declare a catch block which catches all types of exceptions, irrespective of their types. In such catch block, instead of declaring a certain type of exception it can catch, we are going to use three dots(...) within its parenthesis.



#include<iostream>


using namespace std;

class A
{
public:
char ch ='c';
int i  = 1;

void function1();
void function2();
};


void A :: function1()
{
if(ch == 'c')
	throw(ch);
}

void A :: function2()
{
if(i == 1)
	throw(i);
}



int main()
{
A ob;
try
{	
	ob.function1();			
}
catch(...)     //catch block to handle/catch exception
{
	cout<<"A catch block for all types of exceptions has caught an exception \n";
}

try
{
	ob.function2();
}
catch(...)     //catch block to handle/catch exception
{
	cout<<"A catch block for all types of exceptions has caught an exception";
}	
}





Output

A catch block for all types of exceptions has caught an exception
A catch block for all types of exceptions has caught an exception







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