C语言求圆的面积和周长

#include
#include
double f(double r)
{
double s;
s=r*r*3.14;
return s;
}
double g(double r)
{
double c;
c=r*2*3.14;
return c;
}
main()
{
double r;
double s,c;
printf("请输入圆的半径\n");
scanf("%d",&r);
s=f(r);
printf("圆的面积=%d\n",s);
c=g(r);
printf("圆的周长=%d\n",c);
printf("按任意键退出\n");
getch();
return 0;
}
求帮忙看看这段函数哪里 出错了，可以运行但是不能得到正确的答案

#define n 3.1415926#includevoid main(){ double s,l,r; scanf("%lf",&r); s=n*r*r; l=2*n*r; printf("s=%lf\n l=%lf\n",s,l); //float 对应%f double对应 %lf}

#include<stdio.h> #define pi 3.1415926 double area(double r) { return pi * r * r; } double perimeter(double r) { return 2 * pi * r; } int main() { printf("请输入半径的值:\n"); double r; scanf("%lf",&r); printf("周长为%lf\n",perimeter(r)); printf("面积为%lf\n",area(r)); return 0;