有唯一解的高斯消元模板

/*有唯一解的高斯消元模板*/#include<stdio.h>#include<iostream>#include<math.h>#include<algorithm>using namespace std;#define N 110double a[N][N];void gauss(int n) {  int i,j,k,r;  for(i=0;i<n;i++) {    r=i;    for(j=i+1;j<n;j++)        if(fabs(a[j][i])>fabs(a[r][i]))r=j;    if(fabs(a[r][i])<=1e-10)continue;    if(r!=i)        for(j=0;j<=n;j++)swap(a[r][j],a[i][j]);        for(k=0;k<n;k++)            if(k!=i)            for(j=n;j>=i;j--)            a[k][j]-=a[k][i]/a[i][i]*a[i][j];  }  for(i=n-1;i>=0;i--) {    for(j=i+1;j<n;j++)        a[i][n]-=a[j][n]*a[i][j];    a[i][n]/=a[i][i];  }}int main() {     int  i,j,n;     scanf("%d",&n);     for(i=0;i<n;i++)        for(j=0;j<n+1;j++)            scanf("%lf",&a[i][j]);        gauss(n);        for(i=0;i<n;i++)            printf("%lf ",a[i][n]);return 0;}