Arrays of Structures

ARRAYS OF STRUCTURES

In the above examples, we have seen how to declare a structure and assign values to its data members. Now we will discuss how to declare an array of a structure. For this purpose, let us first analyse, where we would need array of structures.

Programming Tip: It is an error to omit array subscripts when referring to individual structures of an array of structures.

In a class, we do not have just one student. But there may be at least 30 students. So the same definition of the structure can be used for all the 30 students. This would be possible when we create an array of the structure. An array of a structure is declared in the same way as we declare an array of a built-in data type.

Another example where an array of structures is desir- able is in case of an organization. An organization has a number of employees. So, defining a separate structure for every employee is not a viable solution. So here we can have a common structure definition for all the employees. This can again be done by declaring an array of the struc- ture employee.

The general syntax for declaring an array of a structure can be given as

struct struct name

{

data_type member_name1;

data_type member_name2;

data_type member_name3;

…………………………………

};

struct struct_name struct_var [index];

Consider the given structure definition.

struct student

{

int r_ no;

char name [20];

char course [20];

float fees;

};

A student array can be declared simply by writing

student stud [30];

Now, to assign values to the ith student of the class, we will write,

stud[i].r_no = 09;

stud[i].name = "RASHI";

stud[i].course = "MCA";

stud[i].fees = 60000;

In order to initialize the array of structure variables at the time of declaration, you should write as follows:

student stud [3] = {{01, "Aman", "BCA", 45000}, {02, "Aryan", "MCA", 60000}, {03, "John", "BCA", 45000}};

6. Write a program to read and display the information of all the students in the class.

#include <stdio.h>

#include <conio.h>

int main()

{

struct student

{

int roll_no;

char name [80];

int fees;

char DOB [80];

};

struct student stud [50];

int n, i;

clrscr();

printf("\n Enter the number of students: ");

scanf("%d",&n);

for (i = 0; i < n;i++)

{

printf("\n Enter the roll number: ");

scanf("%d", &stud [i].roll_no);

printf("\n Enter the name: ");

gets (stud [i].name);

printf("\n Enter the fees: ");

scanf("%d", &stud [i].fees);

printf("\n Enter the DOB: ");

gets (stud [i].DOB);

}

for (i=0;i<n;i++)

{

printf("\n ********DETAILS OF STUDENT %d ******", i+1);

printf("\n ROLL No. = %d", stud[i]. roll_no);

printf("\n NAME = %%s", stud[i].name);

printf("\n FEES = %d", stud[i].fees);

printf("\n DOB = %s", stud [i].DOB);

}

getch();

return 0;

}

Output

Enter the number of students: 2

Enter the roll number: 1

Enter the name: kirti

Enter the fees: 5678

Enter the DOB: 9 9 91

Enter the roll number: 2

Enter the name: kangana

Enter the fees: 5678

Enter the DOB: 27 8 91

********DETAILS OF STUDENT 1*******-

ROLL No. = 1

NAME = kirti

FEES = 5678

DOB = 9 9 91

********DETAILS OF STUDENT 2****

ROLL NO. = 2

NAME = kangana

FEES = 5678

DOB = 27 8 91

7. Write a program to read and display the information of all the students in the class. Then edit the details of the ith student and redisplay the entire information.

#include <stdio.h>

#include <string.h>

#include <conio.h>

int main()

struct student

{

int roll no;

char name [80];

int fees;

char DOB [80];

};

struct student stud [50];

int n, i, rolno, new_rolno;

int new_fees;

char new_DOB [80], new_name [80];

clrscr();

printf("\n Enter the number of students: ");

scanf("%d", &n);

for (i = 0;i<n;i++)

{

printf("\n Enter the roll number: ");

scanf("%d", &stud[i].roll_no);

printf("\n Enter the name: ");

gets (stud [i].name);

printf("\n Enter the fees: ");

scanf("%d", stud[i].fees);

printf("\n Enter the DOB: ");

gets (stud [i].DOB);

}

for (i = 0;i < n;i++)

{

printf("\n ******DETAILS OF STUDENT %d*******", i+1);

printf("\n ROLL No. = %d", stud[i]. = roll_no);

printf("\n NAME =%s", stud[i].name)

printf("\n FEES %d", stud[i].fees);

printf("\n DATE OF BIRTH = %s",stud [i].DOB);

}

printf("\n Enter the roll no. of the student whose record has to be edited: ");

scanf("%d", &rolno);

printf("\n Enter the new roll number: ");

scanf("%d", &new_rolno);

printf("\n Enter the new name:");

scanf("%s", new_name);

printf("\n Enter the new fees: ");

scanf("%d", &new_fees);

printf("\n Enter the new date of birth: ");

scanf("%s", new_DOB);

stud [rolno]. roll_no = new_rolno;

strcpy (stud [rolno]. name, new_name);

stud [rolno].fees = new_fees;

strcpy(stud [rolno]. DOB, new_DOB);

for (i=0;i<n;i++)

{

printf("\n ********DETAILS OF STUDENT %d*******", i+1);

printf("\n ROLL No.= %d", stud[i].roll_no);

printf("\n NAME = %s", stud[i].name);

printf("\n FEES = %d", stud[i].fees);

printf("\n DATE OF BIRTH = %s", stud[i].DOB);

}

getch();

return 0;

}

Output

Enter the number of students: 2

Enter the roll number: 1

Enter the name: kirti

Enter the fees: 5678

Enter the DOB: 9 9 91

Enter the roll number: 2

Enter the name: kangana

Enter the fees: 5678

Enter the DOB: 27 8 91

********DETAILS OF STUDENT 1*******

ROLL NO. = 1

NAME = kirti

FEES = 5678

DOB = 9 9 91

********DETAILS OF STUDENT 2***

ROLL NO. = 2

NAME = kangana

FEES = 5678

DOB = 27 8 91

Enter the roll no. of the student whose record has to be edited: 2

Enter the new roll number: 2

Enter the new name: kangana khullar

Enter the new fees: 7000

Enter the new date of birth: 27 8 92

********DETAILS OF STUDENT 1**********

ROLL No. = 1

NAME = kirti

FEES = 5678

DOB = 9 9 91

********DETAILS OF STUDENT 2*********

ROLL NO.= 2

NAME = kangana

FEES = 7000

DOB = 27 8 92