c语言.用函数正方形里面有一个内切圆.输入半径.求正方形面积.圆面积.再相加. 求修改!!指点!!!

Question

#include<stdio.h>
#define PI 3.14
float r,sum,area,adding;
float yuan(float r) //圆
{
float area;
area=r*r*PI;
return area;
}
float zfx(float r) //正方形
{
float sum;
sum=r*r;
return sum;
}
main()
{
float daan ;
printf("输出圆的半径:");
scanf("%f",&r);
yuan(r);
zfx(r);
daan=sum+area;
printf("正方形加圆形和等于%f:",adding);
return 0;
}

Answer 1

#include<stdio.h>
#define PI 3.14
float yuan(float r) //圆
{
float area;
area=r*r*PI;
return area;
}
float zfx(float r) //正方形
{
float sum;
sum=4*r*r;
return sum;
}
main()
{
float daan ;
printf("输入圆的半径:");
scanf("%f",&r);
daan=yuan(r)+zfx(r);
printf("正方形加圆形和等于:%f",daan);
return 0;
}