C - Structure and Union Question & Answer

Structure and Union Question Answer

Question : What is a structure?

Answer : Structure constitutes a super data type which represents several different data types in a single unit. A structure can be initialized if it is static or global.

Question : What is a union?

Answer : Union is a collection of heterogeneous data type but it uses efficient memory utilization technique by allocating enough memory to hold the largest member. Here a single area of memory contains values of different types at different time. A union can never be initialized.

Question : What the advantages of using Unions?

Answer : When the C compiler is allocating memory for unions it will always reserve enough room for the largest member.

Question :  What are the differences between structures and union?

Answer : A structure variable contains each of the named members, and its size is large enough to hold all the members. Structure elements are of same size. A union contains one of the named members at a given time and is large enough to hold the largest member. Union element can be of different sizes.

Question : What are the differences between structures and arrays?

Answer :Structure is a collection of heterogeneous data type but array is a collection of homogeneous data types.

Array

1-It is a collection of data items of same data type.

2-It has declaration only

3-.There is no keyword.

4- array name represent the address of the starting element.

Structure

1-It is a collection of data items of different data type.

2- It has declaration and definition

3- keyword struct is used

4-Structure name is known as tag it is the short hand notation of the declaration