用自定义函数求圆半径和周长，但是输出没有经过函数计算是什么原因

Question

#include"stdio.h"
#include"stdlib.h"
#define pi 3.14
double square(double n)
{
double r,s;
s=rrpi;
return s;
}
double perimeter(double n)
{
double r,c;
c=2rpi;
return c;
}
double main()
{
double n;
printf("请输入半径的值:");
scanf("%2f",&n);
printf("\n圆的面积s=%2f",square(n));
printf("\n,圆的周长c=%2f",perimeter(n));
return 0;
}

Answer 1

#include"stdio.h"
#include"stdlib.h"
#define pi 3.14
double square(double r)
{
return r * r * pi;
}
double perimeter(double r)
{
return 2 * r * pi;
}
double main()
{
double n;
printf("请输入半径的值:");
scanf("%lf", &n);
printf("\n圆的面积s=%6.2lf", square(n));
printf("\n圆的周长c=%6.2lf", perimeter(n));
return 0;
}

注意：s=rrpi,不能这样写，用*运算符分开。
double对应的是lf