#include<stdio.h>
#include<math.h>
#define N 20
#define EPSILON 0.000000001
void main()
{
    int i,j,k,n,i0;double t;
    double a[N][N+1];
    printf("数组的维数n\n");
    scanf("%d",&n);
    printf("输入a[i][j]\n");
    for(i=0;i<n;i++)
        for(j=0;j<n+1;j++)
            scanf("%lf",&a[i][j]);
   
    /*找列主元 并消去*/
    for(k=0;k<n;k++)
    {
        t=fabs(a[k][k]);i0=k;
        for(i=k+1;i<n;i++)
            if(fabs(a[i][k])>t)
            {
                t=fabs(a[i][k]);
                i0=i;
            }
        /*交换这两行*/
        if(i0!=k)
        {
            for(j=k;j<n+1;j++)
            {
                t=a[i0][j];
                a[i0][j]=a[k][j];
                a[k][j]=t;
            }
            
        }
        for(i=0;i<n;i++)
            for(j=0;j<n+1;j++)
                printf("%12.9f",a[i][j]);
            
        if(fabs(a[k][k])<EPSILON)
            break;
        else for(j=k+1;j<n+1;j++)
        {
            a[k][j]=a[k][j]/a[k][k];
           
             a[k][k]=1.0;
        }/*为什么此时只进行了2步*/
        for(i=0;i<n;i++)
        {
            if(i!=k)
            {
            
                for(j=k+1;j<n;j++)
                    a[i][j]=a[i][j]-a[i][k]*a[k][j];
                 a[i][k]=0.0;
            }
        }
        for(i=0;i<n;i++)
           for(j=0;j<n+1;j++)
              printf("%12.9f",a[i][j]);
        

    }
   
    printf("\n方程组的解为\n");
    for(i=0;i<n;i++)
        printf("x%d=%12.9f\n",i+1,a[i][n]);

}

运行时我程序中说的那个地方,就是我疑惑的地方

有人帮忙解决一下么,为什么给出4维的矩阵,却只运行了2步

还是没解决,跪求阿