C Programming - Structures, Unions, Enums - Discussion

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.

Can anyone explain more about Enum....plz

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

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.

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

The working of structure and union is the same but the difference is in their memory allocation. The size of an structure is the summation of his all the member's size while the size of a union is the same as his largest member's size.

Difference between structure and union is that......

Structure
structure allocates individual memory to all the variables declared in the structure based on there data types

whereas.....

unions allocation the memory takes place based on the variable which occupies largest memory space based on there data type

for example

if in a union 2 variables with data types char and int are given then it allocates a memory of 4 byte in GCC since it occupies more space than char the same memory is shared for both of them

Can any one explain differnce between struct and enum ?

@Priya: In structure only collection of different type of variables which are binded in one unit but enum are they who allows us to assign a particular value from given set to variable.

ex:
enum days {MON=-1, TUE, WED, THU, FRI, SAT};

//This allows days to have val from MON,TUE, WED,THU,FRI,SAT
Whose vaule are from -1 to 4. As MON=-1,TUE=0.