= =、也许我不该用double

#include

#include

using namespace std;

int main()

{

double x1,x2,y1,y2,x,y,sx,sy,r,side;

x1=-1;side=0;

int n,i;

cin>>n>>r;

for(i=0;i>x1>>y1>>x2>>y2;

sx=x1;sy=y1;

}

else

{

x1=x;y1=y;

cin>>x2>>y2;

}

y=y2;x=x2;

x2-=x1;y2-=y1;

side+=sqrt(x2*x2+y2*y2);

}

x2=sx;y2=sy;

x1=x;y1=y;

x2-=x1;y2-=y1;

side+=sqrt(x2*x2+y2*y2);

side+=2*3.141592653589793238462643383279*r;

printf("%.2f",side);

return 0;

}

帖个源程序……各种输出方式都试过了，就是第三个数据不对。