Structures in C
Definition: It is a collection of dissimilar type of elements. Structures are user defined data types.
"struct" is a keyword to define structures.
Declaration:
Syntax :
struct tag_name
{
data_type member1;
data_type member2;
data_type member3;
=================;
=================;
=================;
}; Ã
end of statement
Eg:
struct Employee
{
int empNum;
char
empName[30];
float
salary;
char
dept[15];
};
Structure is an abstract idea of something. Structure members do not acquire any memory without declaring variable for the structure
Declaring a structure variable:
data_type
var_name;
E.g.: struct
Employee emp1, emp2;
in above Example,
struct
Employee à is data type.
emp1 and emp2 Ã are the structure variables.
Memory map of structure members:
emp1
empNum empName salary dept
|
2
bytes |
30
bytes |
4bytes |
15 bytes |
|------------------------------------ 51
byes -----------------------------------------------------------|
emp2
empNum empName salary dept
|
2
bytes |
30
bytes |
4bytes |
15
bytes |
|------------------------------------ 51
byes ------------------------------------------------------------|
Accessing structure members:
" . dot ( period operator )" is an operator to access structure members.
emp1. empNum; emp2 . empNum
emp1. empName; emp2 . empName
emp1. salary; emp2 . salary
emp1. dept; emp2 . dept
Assignment:
emp1. empNum = 1001 ; emp2
. empNum=1002;
strcpy(emp1. empName, "dsk") ; strcpy(emp2 .
empName,"dsk1");
emp1. salary= 5000.00; emp2
. salary=6000.00;
strcpy(emp1. dept,"admin"); strcpy(emp2
. dept,"IT");
emp1
empNum empName salary dept
|
1001 |
dsk\0 |
5000.00 |
Admin\0 |
emp2
empNum empName salary dept
|
1002 |
dsk1\0 |
6000.00 |
IT\0 |
Initialization:
struct
Employee
emp={1001,”nrit1”,5000.50,”admin”};
Reading from key board:
scanf(“%d %s %f
%s”,& emp1. empNum, emp1. empName,
& emp1. salary, emp1. dept );
Displaying structure variables:
printf(“%d %s %f
%s”, emp1. empNum, emp1. empName,
emp1. salary, emp1. dept );
program to read and display Book details.
#include<stdio.h>
main()
{
struct Book
{
int id;
char title[20];
float
price;
char author[20];
char
publisher[20];
};
struct Book b1;
printf("\n Enter Book Details");
printf("\n Enter Id:");
scanf("%d",&b1.id);
printf("\n Enter Title");
scanf("%s",b1.title);
printf("\n Enter price");
scanf("%f",&b1.price);
printf("\n Enter author");
scanf("%s",b1.author);
printf("\n Enter publisher");
scanf("%s",b1.publisher);
printf("\n Book Details are :");
printf("\n Id :
%d",b1.id);
printf("\n Title : %s",b1.title);
printf("\n Price : %f",b1.price);
printf("\n Author : %s",b1.author);
printf("\n Publisher : %s",b1.publisher);
getch();
}
program
to read and display five employees details:
#include<stdio.h>
struct Employee
{
int eno;
char ename[20];
float salary;
char dept[20];
};
main()
{
struct
Employee emp[5];
int
i;
for(i=0;
i<5 ; i++)
{
printf("\n Enter emp details ");
printf("\n Emp number :");
scanf("%d",&emp[i].eno);
printf("\n Emp name :");
scanf("%s",emp[i].ename);
printf("\n Emp salary :");
scanf("%f",&emp[i].salary);
printf("\n Emp Dept:");
scanf("%s",emp[i].dept);
}
printf("\n
Num \t Name \t Salary \t Dept ");
for(i=0;
i<5 ; i++)
{
printf("\n%d \t %s \t %f \t %s
",emp[i].eno,emp[i].ename,emp[i].salary,emp[i].dept);
}
getch();
}
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