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Structures Homework Help

Structures are among the most important items in C Programming Language. It is difficult to program using only Int, Float and Char. In real life Programming, instead of these data types we use a data type which includes these data types. For example, to describe a car we need to tell its Manufacturer, Model no, Color, and Number. We can think of car as a Structure with following definition:

car
{
char manufacturer[50];
int model_no;
char color[10];
int number;
}

A Structure is a collection of Variables under a single name. These Variables can be of different types and each has a name which is used to select it from the Structure. A Structure is a convenient way of grouping several pieces of related information together.

A Structure can contain any valid data types like Int, Char, Float even Arrays and other Structures. Each Variable in Structure is called a Structure member.

Defining Structure

To define a Structure, you can use Struct Keyword. Here is the common syntax of Structure Definition:
struct struct_name{ structure_member };


The name of Structure is followed the rule of Variable Name.
struct book
{
char name;
float price;
int pages;
};


To define instances of book type Structure, we use following:

struct book b1, b2, b3;

A Structure could be complex if it contains other Structures inside itself.

Accessing Members

We use .(dot) to access the element/member of a Structure.

For example, b1.name will return the name of b1 book.


Where we have a Pointer to a Structure we could dereference the Pointer and then use dot as a member selector. This method is a little clumsy to type. Since selecting a member from a Structure Pointer happens frequently, it has its own operator -> which acts as follows. Assume that book_ptr is a Pointer to a Structure of type book. We would refer to the name member as:

Book_ptr -> name

Type Def Keyword

To make your source code more concise, you can use typedef keyword to create a synonym for a Structure. For example:
typedef struct
{
char name[50];
int roll_no;
} student;
student s1, s2;


After using typedef keyword we don't need to use struct word all the time.
Structures Homework Help

Size Of Function

sizeof Function is used to determine the size of any Data-Type. As a Structure is also a Data-Type it works with Structure as well. For example:
sizeof(student) = 50 + 4 = 54 Bytes
where student is the Structure defined above.

Topics in C Programming