#define pi 3.14159 /*定义宏常量pi*/
main ()
{
double r;
double area;
double v;
printf ("input r:");
scanf ("%lf",&r);
area=4*pi*r*r ;/*编译时将被替换成area=4*3.14159*r*r;*/
v=4.0/3*pi*r*r*r;/*编译时将被替换成v=4.0/3.14159*r*r*r;*/
printf("area=%f\n",area);
printf("v=%f\n",v);
}