Structures and Unions, Giving values to members, Initializing structure, Functions and structures, Passing structure to elements to functions, Passing entire function to functions, Arrays of structure, Structure within a structure and Union.
Union is a collection of data items of different data types. It can hold data of only one member at a time though it has members of different data types. If a union has two members of different data types, they are allocated the same memory.
A structure is a user defined data type. We know that arrays can be used to represent a group of data items that belong to the same type, such as int or float. However we cannot use an array if we want to represent a collection of data items of different types using a single name. A structure is a convenient tool for handling a group of logically related data items.