Pointer to array and pointer to structure . how to access elements of array and structure using pointer

1. Pointer to Array and
Structure
Prepared By: Mr. S. A. Patil
Assistant Professor,PVPIT Budhgaon

2. Pointers to Array
 Array is collection elements with same datatype.
 When we create an array some memory space is allocated to that array.
 So we can create pointer of array also.
 By using pointer to array we can access elements of array

3. Example
int numbers[5]={10,20,30,40,50};
int *p;
p=&numbers; // p=numbers;
this store address of first element of the array. And once we store address of first
element of array we can access by using *(p+1),*(p+2) and so on.

4. Access array using pointer
int numbers[5]={10,20,30,40,50};
int *p,i;
p=&numbers; // p=numbers;
for( i=0; i<5 ; i++)
{
printf(“n%d”,*(p+i));
}

5. Pointer to structure
 Structure is collection of elements with different datatypes.
 When we define any structure we create a user defined datatype of structure type.
 Memory is allocated to each structure variable.
 We can also create pointer to structure variable.
 And access structure by using pointer

6. Example
struct student
{
int roll;
float marks;
};
struct student s1;
struct student *ptr;
ptr=&s1;

7. Access structure elements using pointer
 We can access structure elements by using -> operator
 Write data into structure variable
printf(“nEnter Roll No:”);
scanf(“%d”,&ptr->roll);
printf(“nEnter Marks:”);
scanf(“%f”,&ptr->marks);
 Read structure variable
printf(“nRoll number: %d”,ptr->roll);
printf(“nMarks: %f”,ptr->marks);

8. Pointer to array of structure
 It is possible to create pointer to array of structure as regular array.
struct student
{
int roll;
float marks;
};
struct student s[5];
struct student *ptr;
ptr=&s;

9. Access array of structure using pointer
 We can access structure elements by using -> operator
 Write data into structure variable
for(i=0;i<5;i++)
{
printf(“nEnter Roll No:”);
scanf(“%d”,&ptr->roll);
printf(“nEnter Marks:”);
scanf(“%f”,&ptr->marks);
ptr++;
}

10. Access array of structure using pointer
 Read structure variable
for(i=0;i<5;i++)
{
printf(“nRoll number: %d”,ptr->roll);
printf(“nMarks: %f”,ptr->marks);
ptr++;
}