Structure declaration in C language

The structure is a collection of different datatype variables, grouped together under a single name. It is a heterogeneous collection of data items that share a common name.

Features of structure

• It is possible to copy the contents of all structural elements of different data types to another structure variable of its type by using an assignment operator.

• To handle complex datatypes, it is possible to create a structure within another structure, which is called nested structures.

• It is possible to pass an entire structure, individual elements of structure, and address of structure to a function.

• It is possible to create structure pointers.

The general form of structure declaration is as follows −

datatype member1;
struct tagname{
   datatype member2;
   datatype member n;
};

Here,

• struct is the keyword.

• tagname specifies the name of a structure

• member1, member2 specifies the data items that makeup structure.

For example,

struct book{
   int pages;
   char author [30];
   float price;
};

Structure variables

There are three ways of declaring structure variables, which are as follows −

Type 1

struct book{
   int pages;
   char author[30];
   float price;
}b;

Type 2

struct{
   int pages;
   char author[30];
   float price;
}b;

Type 3

struct book{
   int pages;
   char author[30];
   float price;
};
struct book b;