算法1

对角线都输入1，规律是从每行的对角线开始向右和向下递增

#include <iostream>
using namespace std;
sonst in N = 110;
int a[N][N];//数组比较大直接定义成全局数组避免因内存出错
int main()
{
    int n;
    while(cin >> n, n)
    {
        for (int i = 0; i < n; i ++)
        {
            for (int j = i, k = 1; j < n; j ++, k ++)
            {
                a[i][j] = k;
                a[j][i] = k;
            }
        }
        for (int i = 0; i < n; i ++)
        {
            for (int j = 0; j < n; j ++)
            {
                cout << a[i][j] << ' ';
            }
            cout << endl;
        }
        cout << endl;
    }
    return 0;
}

算法2

算法2 没用到数组 一行一行的输入 在对角点之前的部分从行号开始递减到1；对角点向右递增
注意二维矩阵里很多关系都是 j - i + 1之类的

#include <iostream>
using namespace std;
int main()
{
    int n;
    while(cin >> n, n)
    {
        for (int i = 1; i <= n; i ++) 
        {
            for (int j = i; j >= 1; j --) cout << j << ' ';
            for (int j = i + 1, k = 2; j <= n; j ++,k ++) cout << k << ' ';
    //有规律 可以改成 for (int j = i + 1; j <= n; j++ ) cout << j - i + 1<< ' ';
            cout << endl;
        }
        cout << endl;
    }
    return 0;
}

算法3

算法3 就是规律 每个位置的值是 | i - j| + 1

#include <iostream>
using namespace std;
int main()
{
    int n;
    while(cin >> n, n)
    {
        for (int i = 0; i < n; i ++) 
        {
            for (int j = 0; j < n; j ++) 
                cout << abs ( i - j ) + 1 << ' ';
            cout << endl;
        }
        cout << endl;
    }
    return 0;
}