/* gran.c - gaussian random number generator */double ran();                            /* uniform generator */double gran(m, s, iseed)                 /* usage: x = gran(m, s, &iseed); */double m, s;                             /* \(m\) = mean, \(s\sp{2}\) = variance */long *iseed;                             /* iseed passed by address */{       double v = 0;       int i;       for (i = 0; i < 12; i++)          /* sum 12 uniform random numbers */              v += ran(iseed);       return s * (v - 6) + m;           /* adjust mean and variance */}