8.4 POINTERS AND ONE DIMENSIONAL ARRAYS

An array name is really a pointer to the first element in the array. Therefore, if x is one dimensional array, then the address of the first array element can be expressed as either &x[0] or simply as x. Moreover, the address of second array element can be written as either &x[1] or as (x+1), and so on.

Since &x[i] and (x+i) both represent the address of the ith element of x, it would seem reasonable that x[i] and *(x+i) both represent the content of the address i.e., the value of the ith element of x.

Here is a simple C program that illustrates the relationship between array elements and their addresses.

#include < stdio.h >

main()

{

static int x[10] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19 };

int i;

for (i = 0;i <= 9; ++i)  {

/*display an array element*/

printf("\ni= %d   x[i]= %d   *(x+i)= %d", i, x[i], *(x+i));

/*display the corresponding array address*/

printf("    &x[i]=  %X    x+i=  %X",  &x[i], (x+i));

}

}

Execution of the program results in the following output.

i=0  x[i]=10  *(x+i)=10  &x[i]=72   x+i =72

i=1  x[i]=11  *(x+i)=10  &x[i]=74   x+i =74

i=2  x[i]=12  *(x+i)=10  &x[i]=76   x+i =76

i=3  x[i]=13  *(x+i)=10  &x[i]=78   x+i =78

i=4  x[i]=14  *(x+i)=10  &x[i]=7A  x+i =7A

i=5  x[i]=15  *(x+i)=10  &x[i]=7C  x+i =7C

i=6  x[i]=16  *(x+i)=10  &x[i]=7E  x+i =7E

i=7  x[i]=17  *(x+i)=10  &x[i]=80   x+i =80

i=8  x[i]=18  *(x+i)=10  &x[i]=82   x+i =82

i=9  x[i]=19  *(x+i)=10  &x[i]=84   x+i =84