7/31/08

Clashing for enumerations.

When we use enumerations, by default the values assigned to enumerations start from zero. Suppose you have two classes with classA and classB with enumeraions defined as below.

For classA: enum { santro,zen } cars;

For classB: enum { Kinetic,sunny} bikes;

Now in a function you get some integer which should indicate the type of car or type bike.

void findType(int nType)

{

if( nType == classA::santro )

{

cout<

}

if( nType == classA::zen)

{

cout<

}

if( nType == classB::kinetic)

{

cout<

}

if( nType == classB::sunny)

{

cout<

}

}

Now with such a code you will always find out put as

santro

kinetic

OR

zen

sunny

This is because though while coding we use classA::santro and classB::kinetic, both the variables have the same value i.e. zero. Thus for any value of nType (0 or 1 ), always two if conditions are satisfied, giving the wrong result . So if you are using two enumeraions in a single function you should always make sure to avoid the clash between them.

For this we can use the following code to add the offset to one of the enumeraions.

enum { kinetic = 100, sunny } bikes;

Thus values of the enums bikes and cars, will differ in value and the clashing between the two will be avoided.( You also have to adjust the values of the variable nType passed to the function accordingly.)

If two enumeraions are being used in same function, then care should be taken to avoid the clashing between the two.


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