还有没有其他的做法啊?

#include "stdio.h"
main()
{
float x,y,s;
float area(float x,float y);
scanf ("%f%f",&x,&y);
s=area(x,y);
printf("the area is : %.2f\n",s);
}
float area(float x,float y)
{
  float z;
  z=x*y;
  return z;
  }

这是一种.

#include<stdio.h>

#define area(x,y)   x*y

AREA(float AR)
{
  
  
  return AR;
}  
void main()
{
  float x,y,z;
  
  scanf("%f,%f",&x,&y);
  
  AREA(area(x,y));
  
  z=AREA(area(x,y));
  
  printf("%f\n",z);
}

这一种

#include<stdio.h>
#define area(x,y)   x*y  
void main()
{
  float x,y;  
  scanf("%f,%f",&x,&y);  
  printf("%f\n",x?area(x,y):y);
}

输出加.2f.

#include "stdio.h"
main()
{
    float x,y,s;
    scanf ("%f %f", &x, &y);
    s = x * y;
    printf("the area is : %.2f\n",s);
}

#define area(x,y)   ((x)*(y))