Structure Function Array Pointer

Structure and Function

Structures can also be passed as a parameter to a function. This is a powerful feature that greatly simplifies the use of functions thus writing of well-constructed modular programs that use structure.

struct student getdata( );
void list ( struct student);
struct student
{
		char name[30];
		int no;
};
void main(void)
{
        struct student s1=getdata();
	struct student s2=getdata();
	list(s1);
	list(s2);
}
struct student getdata()
{
	struct student temp;
	printf(“Enter your name : “);
	gets(temp.name);
	printf(“Enter Roll No  :”);
	scanf(“%d”,&temp.no);
	return(temp);
}
void list(struct student temp)
{	
	printf(“ Name = %s”, temp.name);
	printf(“ Roll No = %d”, temp.no);
}

Array of Structures

 A structure may occur as an array element. Example:

struct student 
{
		char id[9];
		char name[30];
		int mark;
};

int main(void)
{
	struct student stulist[100];
	...
}

Nested Structure

A nested structure is sometimes called the structure of the structure.

#include <stdio.h>
struct date 
{
	int day;
	int month;
	int year;
};
struct book 
{
	char author[30];
	char title[50];
	char publisher[30];
	int edition;
	struct date date_of_pub;
};
int main(void)
{
	struct book  booklist[100];
	strcpy(booklist[10].author, "Al Kelly");
	strcpy(booklist[10].title, "C By Dissection");
	strcpy(booklist[10].publisher, "Addison-Wesley");
	booklist[10].edition = 3;
	booklist[10].date_of_pub.day = 1;
	booklist[10].date_of_pub.month = 2;
	booklist[10].date_of_pub.year = 1996;
	return 0;
}

Pointer to Structure

Example 1

struct date 
{
	int day;
	int month;
	int year;
};
void  main(void) 
{
	struct date today;
	struct date *ptrDate;
	ptrDate=&today;
	
	(*ptrDate).day = 25;
	(*ptrDate).month = 12;
	(*ptrDate).year = 1997;
	 
      if (today.day==1 && today.month==1)
		printf(“Happy New Year !\n");
}

Example 2

struct date 
{
	int day;
	int month;
	int year;
};
void  main(void) 
{
	struct date today;
	struct date *ptrDate;
	ptrDate=&today;
	
	ptrDate->day = 25;
	ptrDate->month = 12;
	ptrDate->year = 1997;
	 
      if (today.day==1 && today.month==1)
		printf(“Happy New Year !\n");
}