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Structure

{C}

Programming

Programming for Problem Solving (PPS)

GTU # 3110003

USING

Prof. Nilesh Gambhava

�Computer Engineering Department,�Darshan Institute of Engineering & Technology, Rajkot

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Data Types

C language has built-in datatypes like primary and derived data types.
But, still not all real world problems can be solved using those data types.
We need custom datatype for different situation.

Data types are defined as the data storage format that a variable can store a data.

Data types in C

Primary Data type

(int, float, char)

Secondary Data type

Derived Data type

(array, pointer)

User defined Data type

(structure, union, enum)

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User Defined Datatype

We need combination of various datatypes to understand different entity/object.
Example-1:

Book Title: Let Us C Datatype: char / string

Author: Yashavant Kanetkar Datatype: char / string

Page: 320 Datatype: int

Price: 255.00 Datatype: float

Example-2:

Student Name: ABC Datatype: char / string

Roll_No: 180540107001 Datatype: int

CPI: 7.46 Datatype: float

Backlog: 01 Datatype: int

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What is Structure?

Structure is a collection of logically related data items of different datatypes grouped together under single name.
Structure is a user defined datatype.
Structure helps to build a complex datatype which is more meaningful than an array.
But, an array holds similar datatype record, when structure holds different datatypes records.
Two fundamental aspects of Structure:

Declaration of Structure Variable
Accessing of Structure Member

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Syntax to Define Structure

To define a structure, we need to use struct keyword.
This keyword is reserved word in C language. We can only use it for structure and its object declaration.

Structure_name is name of custom type

memberN_declaration is individual member

Members can be normal variables, pointers, arrays or other structures.
Member names within the particular structure must be distinct from one another.

struct structure_name

{

member1_declaration;

member2_declaration;

. . .

memberN_declaration;

};

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Syntax

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Example to Define Structure

You must terminate structure definition with semicolon ;.
You cannot assign value to members inside the structure definition, it will cause compilation error.

struct student

{

char name[30]; // Student Name

int roll_no; // Student Roll No

float CPI; // Student CPI

int backlog; // Student Backlog

};

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struct student

{

char name[30] = “ABC”; // Student Name

. . .

};

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Example

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Create Structure variable

A data type defines various properties about data stored in memory.
To use any type we must declare its variable.
Hence, let us learn how to create our custom structure type objects also known as structure variable.
In C programming, there are two ways to declare a structure variable:

Along with structure definition
After structure definition

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Create Structure Variable – Cont.

Declaration along with the structure definition

struct structure_name

{

member1_declaration;

member2_declaration;

. . .

memberN_declaration;

} structure_variable;

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struct student

{

char name[30]; // Student Name

int roll_no; // Student Roll No

float CPI; // Student CPI

int backlog; // Student Backlog

} student1;

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Example

Syntax

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Create Structure Variable – Cont.

Declaration after Structure definition

struct structure_name structure_variable;

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struct student

{

char name[30]; // Student Name

int roll_no; // Student Roll No

float CPI; // Student CPI

int backlog; // Student Backlog

};

struct student student1; // Declare structure variable

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Example

Syntax

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Access Structure member (data)

Structure is a complex data type, we cannot assign any value directly to it using assignment operator.
We must assign data to individual structure members separately.
C supports two operators to access structure members, using a structure variable.

Dot/period operator (.)
Arrow operator (->)

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Access Structure member (data) – Cont.

Dot/period operator (.)

It is known as member access operator. We use dot operator to access members of simple structure variable.

Arrow operator (->)

In C language it is illegal to access a structure member from a pointer to structure variable using dot operator.
We use arrow operator to access structure member from pointer to structure.

structure_variable.member_name;

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// Assign CPI of student1

student1.CPI = 7.46;

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pointer_to_structure->member_name;

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// Student1 is a pointer to student type

student1 -> CPI = 7.46;

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Syntax

Example

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WAP to print Odd numbers between 1 to n

#include <stdio.h>

struct student

{

char name[40]; // Student name

int roll; // Student enrollment

float CPI; // Student mobile number

int backlog;

};�int main()

{

struct student student1; // Simple structure variable

// Input data in structure members using dot operator

printf("Enter Student Name:");

scanf("%s", student1.name);

printf("Enter Student Roll Number:");

scanf("%d", &student1.roll);

printf("Enter Student CPI:");

scanf("%f", &student1.CPI);

printf("Enter Student Backlog:");

scanf("%d", &student1.backlog);

// Display data in structure members using dot operator

printf("\nStudent using simple structure variable.\n");

printf("Student name: %s\n", student1.name);

printf("Student Enrollment: %d\n", student1.roll);

printf("Student CPI: %f\n", student1.CPI);

printf("Student Backlog: %i\n", student1.backlog);

}

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Enter Student Name:aaa

Enter Student Roll Number:111

Enter Student CPI:7.89

Enter Student Backlog:0

Student using simple structure variable.

Student name: aaa

Student Enrollment: 111

Student CPI: 7.890000

Student Backlog: 0

Program

Output

Write a program to read and display student information using structure.

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#3110003 (PPS) – Structure

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WAP to print Odd numbers between 1 to n

#include<stdio.h>

struct time {

int hours;

int minutes;

int seconds;

};�int main() {

struct time t1,t2;

int h, m, s;

//1st time

printf ("Enter 1st time.");

printf ("\nEnter Hours: ");

scanf ("%d",&t1.hours);

printf ("Enter Minutes: ");

scanf ("%d",&t1.minutes);

printf ("Enter Seconds: ");

scanf ("%d",&t1.seconds);

printf ("The Time is %d:%d:%d",t1.hours,t1.minutes,t1.seconds);

//2nd time

printf ("\n\nEnter the 2nd time.");

printf ("\nEnter Hours: ");

scanf ("%d",&t2.hours);

printf ("Enter Minutes: ");

scanf ("%d",&t2.minutes);

printf ("Enter Seconds: ");

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Enter 1st time.

Enter Hours: 1

Enter Minutes: 20

Enter Seconds: 20

The Time is 1:20:20

Enter the 2nd time.

Enter Hours: 2

Enter Minutes: 10

Enter Seconds: 10

The Time is 2:10:10

Sum of the two time's is 3:30:30

Program

Output

Write a program to declare time structure and read two different time period and display sum of it.

scanf ("%d",&t2.seconds);

printf ("The Time is %d:%d:%d",t2.hours,t2.minutes,t2.seconds);

h = t1.hours + t2.hours;

m = t1.minutes + t2.minutes;

s = t1.seconds + t2.seconds;

printf ("\nSum of the two time's is %d:%d:%d",h,m,s);

return 0;

}

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Array of Structure

It can be defined as the collection of multiple structure variables where each variable contains information about different entities.
The array of structures in C are used to store information about multiple entities of different data types.

struct structure_name

{

member1_declaration;

member2_declaration;

...

memberN_declaration;

} structure_variable[size];

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Syntax

Prof. Nilesh Gambhava

#3110003 (PPS) – Structure

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WAP to print Odd numbers between 1 to n

#include<stdio.h>

struct student {

char name[20];

int rollno;

float cpi;

};

int main( ) {

int i,n;

printf("Enter how many records u want to store : ");

scanf("%d",&n);

struct student sarr[n];

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

{

printf("\nEnter %d record : \n",i+1);

printf("Enter Name : ");

scanf("%s",sarr[i].name);

printf("Enter RollNo. : ");

scanf("%d",&sarr[i].rollno);

printf("Enter CPI : ");

scanf("%f",&sarr[i].cpi);

}

printf("\n\tName\tRollNo\tMarks\t\n");

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

printf("\t%s\t\t%d\t\t%.2f\t\n", sarr[i].name, sarr[i].rollno, sarr[i].cpi);

}

return 0;

}

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Enter how many records u want to store : 3

Enter 1 record :

Enter Name : aaa

Enter RollNo. : 111

Enter CPI : 7.89

Enter 2 record :

Enter Name : bbb

Enter RollNo. : 222

Enter CPI : 7.85

Enter 3 record :

Enter Name : ccc

Enter RollNo. : 333

Enter CPI : 8.56

Name RollNo Marks

aaa 111 7.89

bbb 222 7.85

ccc 333 8.56

Program

Output

Write a program to read and display N student information using array of structure.

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#3110003 (PPS) – Structure

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Structure using Pointer

Reference/address of structure object is passed as function argument to the definition of function.

#include <stdio.h>

struct student {

char name[20];

int rollno;

float cpi;

};

int main()

{

struct student *studPtr, stud1;

studPtr = &stud1;

printf("Enter Name: ");

scanf("%s", studPtr->name);

printf("Enter RollNo: ");

scanf("%d", &studPtr->rollno);

printf("Enter CPI: ");

scanf("%f", &studPtr->cpi);

printf("\nStudent Details:\n");

printf("Name: %s\n", studPtr->name);

printf("RollNo: %d", studPtr->rollno);

printf(”\nCPI: %f", studPtr->cpi);

return 0;

}

Enter Name: ABC

Enter RollNo: 121

Enter CPI: 7.46

Student Details:

Name: ABC

RollNo: 121

CPI: 7.460000

Program

Output

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Nested Structure

When a structure contains another structure, it is called nested structure.
For example, we have two structures named Address and Student. To make Address nested to Student, we have to define Address structure before and outside Student structure and create an object of Address structure inside Student structure.

struct structure_name1

{

member1_declaration;

member2_declaration;

...

memberN_declaration;

};�struct structure_name2

{

member1_declaration;

member2_declaration;

...

struct structure1 obj;

};

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Syntax

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#include<stdio.h>

struct Address

{

char HouseNo[25];

char City[25];

char PinCode[25];

};�struct Student

{

char name[25];

int roll;

float cpi;

struct Address Add;

};�int main()

{

int i;

struct Student s;

printf("\n\tEnter Student Name : ");

scanf("%s",s.name);

printf("\n\tEnter Student Roll Number : ");

scanf("%d",&s.roll);

printf("\n\tEnter Student CPI : ");

scanf("%f",&s.cpi);

printf("\n\tEnter Student House No : ");

scanf("%s",s.Add.HouseNo);

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Details of Students

Student Name : aaa

Student Roll Number : 111

Student CPI : 7.890000

Student House No : 39

Student City : rajkot

Student Pincode : 360001

Program

Output

Write a program to read and display student information using nested of structure.

printf("\n\tEnter Student City : ");

scanf("%s",s.Add.City);

printf("\n\tEnter Student Pincode : ");

scanf("%s",s.Add.PinCode);

printf("\nDetails of Students");

printf("\n\tStudent Name : %s",s.name);

printf("\n\tStudent Roll Number : %d",s.roll);

printf("\n\tStudent CPI : %f",s.cpi);

printf("\n\tStudent House No : %s",s.Add.HouseNo);

printf("\n\tStudent City : %s",s.Add.City);

printf("\n\tStudent Pincode : %s",s.Add.PinCode);

return 0;

}

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Thank you

✓