POINTERS AND ARRAYS

POINTERS AND ARRAYS

Case 1: generating pointer to array (or) passing pointer to array

• ·        whenever a single dimensional array is declared the C-compiler automatically creates a pointer variable and it stores the base address of the array.
• ·        Now the pointer can refer every element in single dimensional array

                        i.e., &x[i] = x+i                       x[i] = *(x+i)

            #include<stdio.h>

#include<conio.h>

main()

{

int i,a[5],n;

clrscr();

printf("\n Enter n value: ");

scanf("%d",&n);

printf("\n Enter the %d array elements: ",n);

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

scanf("%d",(a+i));

printf("\n The given array elements are: ");

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

printf(" %d",*(a+i));

getch();

}

Case 2: passing pointer to two dimensional array:

• ·        whenever a two dimensional array is declared the C-compiler automatically creates a pointer array with the same name of two dimensional array and it stores the base address of the each row.
• ·        whenever a pointer array is created the C-compiler automatically creates a pointer pointer variable with the same name of the pointer array name and it stores the address of the pointer array.
• ·        Now the pointer can refer every element of two dimensional array

            Similarly, for double dimensional arrays,

            &x[i][j] = (*(x+i)+j)                x[i][j] = *(*(x+i)+j)

            Example program:

#include<stdio.h>

#include<conio.h>

main()

{

int a[3][3],i,j,m,n;

clrscr();

printf("\n Enter m,n values: ");

scanf("%d%d",&m,&n);

printf("\n enter %d*%d elements",m*n);

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

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

scanf("%d", (*(a+i)+j));

printf("\n The array elements are: ");

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

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

printf("%d", *(*(a+i)+j));

getch();

}