怎么画正N边形

[rendy]

已知圆心和半径，怎么等分圆周

[GameWeaverDummy]

用GOOGLE查一下相关的数学知识

[yening0914]

角度问题，很好算的呀，k=360/N,然后x=cos(k),y=sin(k),一个角度一个角度的算就是了！

[寻开心]

N 是边数， N大于2

float fAngle = 0;
for ( int i=0; i<N; i++, fAngle+= 2*Pi/N ) {
xi = r * cos (fAngle)
yi = r * sin (fAngle)
输出xi,yi
};

[寻开心]

POINT * pPoint = new POINT[N];
POINT * pTemp = pPoint;
float fAngle = 0;
for ( int i=0; i<N; i++, fAngle+= 2*Pi/N, pTemp++ ) {
*pTemp.x = r * cos (fAngle)
*pTemp.y = r * sin (fAngle)
};
pDC->Polyline(pPoint, N);
delete[] pPoint;

[smallbull]

int N = 100; //凸N边形,假设为凸100边形
double Radius = 20.00; //圆的半径,假设为20
double DevideAngle,Pai = 3.1415926;//平分角度和圆周率
double CoordinateX[100],CoordinateY[100];//凸100边形的100个顶点的笛卡儿座标
DevideAngle = Pai*360/(N*180);
for(int i=0;i<N;i++)
{
CoordinateX[i] = Radius * cos(DevideAngle);
CoordinateY[i] = Radius * sin(DevideAngle);
}

[itmaster]

学习

[lxstudent]

#define Pi 3.1415926
#define r 100
#include <math.h>


void CMyView::OnDraw(CDC* pDC)
{
CMyDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here
Point point[10];
double fAngle = 0;
CRect rect;
GetClientRect(&rect);
pDC->SetViewportOrg(rect.Width()/2,rect.Height()/2);
pDC->MoveTo(CPoint(r,0));
for ( int i=0; i<10; i++, fAngle+= 2*Pi/10)
{
point[i].x = r * cos (fAngle);
point[i].y= r * sin (fAngle);
pDC->LineTo(CPoint(point[i].x,point[i].y));

}
pDC->LineTo(r,0);
}

[rendy]

用三角函数就行了，太笨了！
哈哈，结贴。

[syy64]

不难