大数相乘？或 相加？

C/C++ code

myCircle CPylonBackCheckView::FittingCircle(vector<int> XX, vector<int> YY , int NUM ){    myCircle circle;    int  x1 = 0,x2 = 0,x3 = 0;    int y1 = 0,y2 = 0,y3 = 0;    int x1y1 = 0,x1y2 = 0,x2y1 = 0;    int xtemp = 0 ;    for (int i = 0; i <  NUM ; i++)    {              x1 = x1 + XX[i];        x2 = x2 + XX[i]*XX[i];        x3 = x3 + XX[i]*XX[i]*XX[i];        y1 = y1 + YY[i];        y2 = y2 + YY[i]*YY[i];        y3 = y3 + YY[i]*YY[i]*YY[i];        x1y1 = x1y1 + XX[i]*YY[i];        x1y2 = x1y2 + XX[i]*YY[i]*YY[i];        x2y1 = x2y1 + XX[i]*XX[i]*YY[i];    }    long double  C = NUM * x2 - x1 * x1;    long  double  D = NUM * x1y1 - x1 * y1;    long double  E = NUM * x3 + NUM * x1y2 - (x2 + y2) * x1;    long double  G = NUM * y2 - y1 * y1;    long double  H = NUM * x2y1 + NUM * y3 - (x2 + y2) * y1;    long double  a = (H * D - E * G)/(C * G - D * D);    long double  b = (H * C - E * D)/(D * D - G * C);                                long double  c = -(a * x1 + b * y1 + x2 + y2)/NUM;    double  A = a/(-2);          //x坐标    double     B = b/(-2);          //y坐标    double  R = sqrt(a * a + b * b - 4 * c)/2;    circle.xCenter = int(A);    circle.yCenter = int(B);    circle.Radius = int(R);    return circle;}

以上代码for循环里面的内容在matlab里能够正确的计算出结果。但是在VC中，x3，y3，x1y2，x2y1计算出来的结果却不正常了。只能有9位，偶尔还有负值出现，XX[i],YY[i]的范围在0~1000；三个连乘最大也就是10的9次方，9个数位。调试发现当y3 = 2128102546，继续加上一个28094464时，y3变成了负数-2138770286.是因为大数相加溢出嘛？可是只有十位数而已啊~~~~~


[解决办法]
数据类型该为 long double试试
[解决办法]
int int32 max value is 4，294，967，295
[解决办法]
int的范围本来就是-2147418112至2147418112
2128102546+28094464 = 2156197010 超过了，所以显示负数
[解决办法]

探讨

int int32 max value is 4，294，967，295

[解决办法]
用DWORD或者DWORD64可以拓展正数的位数哟