#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n,i,j,a[110][110];
    cin>>n;
    for(i=1;i<=n;i++)
    {
    	for(j=1;j<=n;j++)
        {
    		a[i][j]=((i-1)*n)+j;
		}
	}
	for(i=1;i<=n;i++)
    {
		for(j=1;j<=n;j++)
        {
			cout<<setw(3)<<a[i][j];
		}
		cout<<endl;
	}
    return 0;
}//已AC

不用二维数组轻松搞定

#include <iostream>
using namespace std;
int main()
{
    int n;
    cin >> n;
    for (int i=1;i<=n*n;i++)
    {
        if (i<10)
        {
            cout << "  " << i;
        }
        else
        {
            cout << " " << i;
        }
        if (i%n==0)
        {
            cout << endl;
        }
    }
    return 0;
}

哪有这么简单的题啊，真不像话

#include <iostream>
using namespace std;
int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n * n; i++)
    {
        if (i < 10)
        {
            cout << "  ";
        }
        else
        {
            cout << " ";
        }
        cout << i;
        if (i % n == 0)
        {
            cout << endl;
        }
    }
    return 0;
}

#include <iostream>
using namespace std;
int main()
{
    int n, x = 0;
    cin >> n;
    int a[n][n];
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= n; j++)
        {
            x++;
            a[i][j] = x;
            if (x / 10 == 0)
            {
                cout << "  " << a[i][j];
            }
            else
            {
                cout << " " << a[i][j];
            }
        }
        cout << endl;
    }
    return 0;
}

谁说一定要用二维数组的。

#include <iostream>
using namespace std;
int main()
{
    int n;
    cin >> n;
    for(int i=1;i<=n;i++)
    {
        cout << " ";
        for(int j=1;j<=n;j++)
        {
            if((i-1)*n+j<10)
            {
                cout << " ";
            }
            cout << (i-1)*n+j << " ";
        }
        cout << endl;
    }
}