求解释下面的程序作用

#include<stdio.h>
main()
{
    int i,j,k,x1=0,x2=0,y=0,m=0,n,l=0,a[3][3]={1,23,2,7,9,11,13,15,17};
    for(i=0;i<3;i++)
    {
        for(j=0;j<3;j++)
        {
            if(a[i][j]>m)
            {
                m=a[i][j];
                x1=i;
                y=j;
                n=m;
            }
            for(k=0;k<3;k++)
            {
                if(a[k][y]<n)
                {
                    n=a[k][y];
                    x2=k;
                }
            }
        }
        if(x1==x2)
                printf("%d行 %d列 %d\n",x1+1,y+1,a[x1][y]);
        else
            l++;
    }
    if(l>2)
        printf("error\n");
}