C Programming - Structures, Unions, Enums - Discussion

I think structure, union and enum - user defined data type.

I agree with raju he have given a good explanation about these.

In short structures are used to share different memory locations for variable and union is used to allocate large memory for all variables.

I'm agree that structures and union are use to define new data type , but how enumeration is use to define new data type. it just internally store an integer value.

Nice explanation raju. Enum is basically used for storing different datatypes variables. It is follow indexes like{0, 1, 2, . }.

Can anyone explain more about Enum....plz

I agree with runs. He/she said very nice defnition. And one more is the main difference between structure and union is

Structures allocates diffrent memory locations.

Union allocates large memory.

Nice Explanation raju.......

Structure,union,enum all are userdefined datatypes.

Let we take one senario for structure.

Suppose in my programm i've to take the 100 variables. If you want to define many variables of different datatype, instead of declaring all those variables individually just go through sructure.Just define the one structure and take all those variables into that structure.

Then if you want to access any variable, just take the structname and dot operator and variable name.then we can access those variables.

union also used for storing the different datatypes variables. But there is small difference between structure and union.i.e
In structures we can acess all those variables at a time because of they are sharing different memory locations.

But in unions whatever we declare in the union those all are sharing same memory that's why at a time we can access only one variable. enum also used for storing user defined variable

Ex: enum { married,divorced,unmarred}

By defaultley married is indexed by o,divorced is 1, unmarried is 2.

If you want to change this order you can change by using married=10 then divorced = 11, unmarried = 12.

What is union ?

But enum will store's integer constants only. How it can store all types of datatypes.