Structure is user defined data type
which is used to store heterogeneous data under unique name. Keyword 'struct'
is used to declare structure. The variables which are declared inside the
structure are called as 'members of structure'.
Syntax:
struct structure_nm
{
<data-type> element 1;
<data-type> element 2;
- - - - - - - - - - -
- - - - - - - - - - -
<data-type> element n;
}struct_var;
Example :
struct emp_info
{
char emp_id[10];
char nm[100];
float sal;
}emp;
Note :
1. Structure
is always terminated with semicolon (;).
2. Structure
name as emp_info can be later used to declare structure variables of its type
in a program.
* INSTANCES OF STRUCTURE :
Instances of
structure can be created in two ways as,
Instance 1:
struct emp_info
{
char emp_id[10];
char nm[100];
float sal;
}emp;
Instance 2:
struct emp_info
{
char emp_id[10];
char nm[100];
float sal;
};
struct emp_info
emp;
In above
example, emp_info is a simple structure which consists of stucture members as
Employee ID(emp_id), Employee Name(nm), Employee Salary(sal).
* ACEESSING STRUCTURE MEMBERS :
Structure
members can be accessed using member operator '.' . It is also called as
'dot operator' or 'period operator'.
structure_var.member;
Program :
#include <stdio.h>
#include
<conio.h>
struct comp_info
{
char nm[100];
char addr[100];
}info;
void main()
{
clrscr();
printf("\n Enter Company Name :
");
gets(info.nm);
printf("\n Enter Address :
");
gets(info.addr);
printf("\n\n Company Name :
%s",info.nm);
printf("\n\n Address : %s",info.addr);
getch();
}
Output :
Enter Company Name : TechnoExam,
Technowell Web Solutions
Enter Address : Sangli,
Maharashtra, INDIA
Company Name : TechnoExam,
Technowell Web Solutions
Address : Sangli, Maharashtra,
INDIA
Array
in Structures :
#include <stdio.h>
#include <conio.h>
struct result
{
int rno,
mrks[5];
char nm;
}res;
void main()
{
int i,total;
clrscr();
total = 0;
printf("\n\t
Enter Roll Number : ");
scanf("%d",&res.rno);
printf("\n\t Enter
Marks of 3 Subjects : ");
for(i=0;i<3;i++)
{
scanf("%d",&res.mrks[i]);
total =
total + res.mrks[i];
}
printf("\n\n\t
Roll Number : %d",res.rno);
printf("\n\n\t
Marks are :");
for(i=0;i<3;i++)
{
printf("
%d",res.mrks[i]);
}
printf("\n\n\t
Total is : %d",total);
getch();
}
Output :
Enter
Roll Number : 1
Enter
Marks of 3 Subjects : 63 66 68
Roll
Number : 1
Marks
are : 63 66 68
Total
is : 197_
Structure
With Array :
We can create structures with array for ease of operations in
case of getting multiple same fields.
#include <stdio.h>
#include <conio.h>
struct emp_info
{
int emp_id;
char nm[50];
}emp[2];
void main()
{
int i;
clrscr();
for(i=0;i<2;i++)
{
printf("\n\n\t
Enter Employee ID : ");
scanf("%d",&emp[i].emp_id);
printf("\n\n\t
Employee Name : ");
scanf("%s",emp[i].nm);
}
for(i=0;i<2;i++)
{
printf("\n\t Employee ID :
%d",emp[i].emp_id);
printf("\n\t Employee Name :
%s",emp[i].nm);
}
getch();
}
Output :
Enter
Employee ID : 1
Employee
Name : ABC
Enter
Employee ID : 2
Employee
Name : XYZ
Employee
ID : 1
Employee
Name : ABC
Employee
ID : 2
Employee
Name : XYZ_
Structures
within Structures (Nested Structures) :
Structures can be used as structures within structures. It is
also called as 'nesting of structures'.
Syntax:
struct structure_nm
{
<data-type>
element 1;
<data-type>
element 2;
- - - - - - - - -
- -
- - - - - - - - -
- -
<data-type>
element n;
struct
structure_nm
{
<data-type>
element 1;
<data-type>
element 2;
- - - -
- - - - - - -
- - - -
- - - - - - -
<data-type>
element n;
}inner_struct_var;
}outer_struct_var;
Example :
struct stud_Res
{
int rno;
char nm[50];
char std[10];
struct stud_subj
{
char
subjnm[30];
int marks;
}subj;
}result;
In above example, the structure stud_Res consists of stud_subj
which itself is a structure with two members. Structure stud_Res is called as
'outer structure' while stud_subj is called as 'inner structure.' The members
which are inside the inner structure can be accessed as follow :
result.subj.subjnm
result.subj.marks
Program :
#include <stdio.h>
#include <conio.h>
struct stud_Res
{
int rno;
char std[10];
struct stud_Marks
{
char
subj_nm[30];
int subj_mark;
}marks;
}result;
void main()
{
clrscr();
printf("\n\t
Enter Roll Number : ");
scanf("%d",&result.rno);
printf("\n\t
Enter Standard : ");
scanf("%s",result.std);
printf("\n\t
Enter Subject Code : ");
scanf("%s",result.marks.subj_nm);
printf("\n\t
Enter Marks : ");
scanf("%d",&result.marks.subj_mark);
printf("\n\n\t
Roll Number : %d",result.rno);
printf("\n\n\t
Standard : %s",result.std);
printf("\nSubject
Code : %s",result.marks.subj_nm);
printf("\n\n\t
Marks : %d",result.marks.subj_mark);
getch();
}
Output :
Enter
Roll Number : 1
Enter
Standard : MCA(Sci)-I
Enter
Subject Code : SUB001
Enter
Marks : 63
Roll
Number : 1
Standard
: MCA(Sci)-I
Subject Code : SUB001
Marks
: 63_
