#include "stdio.h"
  #include "6gsdl.c"
  main()
  { int i;
    double eps;
    static double a[4][4]={ {7.0,2.0,1.0,-2.0},{9.0,15.0,3.0,-2.0},
                          {-2.0,-2.0,11.0,5.0},{1.0,3.0,2.0,13.0}};
    static double x[5],b[4]={4.0,7.0,-1.0,0.0};
    eps=0.000001;
    if (gsdl(a,b,4,x,eps)>0)
      for (i=0;i<=3; i++)
        printf("x(%d)=%13.7e\n",i,x[i]);
  }