Thread: How to use Macros??

Hey peoples im new to macros and i have seem to have gotten the notation for my VOLUME macro, however i dont know what to do for the PRINTSTR macro which is supposed to ask a string for you to input which will then be outputted onto the next line.

Code:

#include <stdlib.h>
#include <stdio.h>

int main()
{
   #define VOLUME(r) ((4.0 /3) * 3.14 * (r)*(r)*(r))
   #define PRINTSTR(str) printf("%s")
   char str[100];
   float r;

   printf("Please enter the radius of a sphere \n");
   scanf("%f", &r);
   printf("The volume of the sphere is: %.2f\n", VOLUME(r));
   printf("Enter a string you want to print \n");
   scanf("%s", str);
   PRINTSTR(str);
   return 0;
}