main( )
{    int x,y;                /*input data */
double power(int, int);    /* prototype declaration*/

    printf(“Enter x,y:”);
    scanf(“%d %d” , &x,&y);
    printf(“%d to power %d is %f\n”, x,y,power (x,y));
}
double power (int x, int y);
{
    double p;
    p = 1.0 ;           /* x to power zero */
if(y >=o)
        while(y--)   /* computes positive powers */

         p *= x;
    elsewhile (y++)  /* computes negative powers */

         p /= x;
        return(p);

    }

Output

    Enter x,y:162
    16 to power 2 is 256.000000

    Enter x,y:16-2
    16 to power -2 is 0.003906