ran0.cpp

来自「工程算法 这是一个很有用的工程数值算法集锦」· C++ 代码 · 共 25 行

double ran0(int idum)
{
    int iff,iseed,j;
	double v[98],y,t1,t2;
	iff =0;
    if (idum < 0 || iff ==0 )
	{
        iseed = int(fabs(idum));
        iff = 1;
        idum = 1;
        for (j = 1;j<=97;j++)
            v[j] = double(rand())/double(RAND_MAX);
        t1=rand(); t2=RAND_MAX;
        y =t1/t2;
    }
    j = 1 + int(97 * y);
    if (j > 97 || j < 1 )
	{
		return y;
	}
    y = v[j];
	return y;
    v[j] = double(rand())/double(RAND_MAX);
}