Introduction to Structure in C

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Introduction to Structure in C

Structure is a user defined data type which is a collection of different variables of different types. 

Syntax for structure is:

struct <struct_name>
{
<type1> var1;
<type2> var2;
:
:
<typeN> var-N;
};

struct is the keyword specifying the beginnning of structure.

struct_name is the name of structure. which should follow rules of a valid identifier of C language.

{ Opening brace specifies that structure has started.

type1, type2,… typeN refer to different data types.

var1, var2,… var-N are variables declared inside the structure. They are also called structure members .

} Closing brace specifies that structure has ended.

; Semicolon should be  written after closing brace.

Example
struct data
{
int a;
float b;
};

In the above example, structure named data has been defined which contains two elements  named a and b.



Declaration of a Structure variable

Variables of a structure can be declared just like variables of other data types.

To declare a variable of structure , struct keyword followed by name of structure followed by structure type variables should be written

Syntax for declaring a structure  variable is:

struct <struct_name> v1,v2,…..vN;

v1,v2,……..vN are structure variables.

Example:

struct data d;

In the above example, variable d has been declared for already declared structure data.



Accessing structure members

Dot (.) operator or arrow operator  -> can be used to put  or access values structure elements through a structure variable.

The syntax:

structvar.member_name;
or
structvar->member_name;

Here, structvar is the name of structure variable and member_name is the element of structure.

Program
#include<stdio.h>
struct data
{
int a;
float b;
};
int main()
{
struct data d;
d.a=13;
d.b=20.55;
printf(“\nd.a=%d”,d.a);
printf(“\nd.b=%f”,d.b);
return(0);
}
Output
d.a=13
d.b=20.549999
Description
In the above program, structure variable d contains 13 for its first element a and 20.55 for its second element b.

 

Initialization of a structure variable

We can initialize a structure variable by putting values within the pair of braces. These values are assigned to the structure elements on one to one basis 

Syntax:

struct <structname><var>={List};

Example:        

struct data
{
int a;
float b;
};
struct data d={20,50.5};

In this example, structure variable d has been initialized with values 20,50.5.  20 would be stored in d.a and 50.5 would be stored in d.b .

Program 
#include<stdio.h>
struct data
{
int a;
float b;
};
int main()
{
struct data d={3,7.8};
printf(“\nd.a=%d”,d.a);
printf(“\nd.b=%f”,d.b);
return(0);
}
Output
d.a=3
d.b=7.800000
Description
In the above program, structure variable d has been initialized to contain 3 for its first element a and 7.8 for its second element b.

 

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Lesson tags: accessing member of structure, create structure in c, creating structure variable in c, initialization of structuer variable, operator used with structure in c, structure operations in c, what is a structure in c
Back to: C Programming Language