第二章例2-4

#include<stdio.h>
int main(void)
{
      double x,y;
  

      printf("Enter x(x>=0):\n");

      scanf("%lf",&x);

      if(x<=15){
         y=4*x/3;
	  }
      else{ 
         y=2.5*x-10.5;
	  }
      printf("y=f(%f)=%.2f\n",x,y);


      return 0;

}