How to find Addition Table using C++

#include <iostream>
#include <cstdio>
using namespace std;
int main()
{
    int n;
    while(cin>>n){
        for(int i=0;i<n;i++){
            int x = i;
            for(int j=0;j<n;j++){
                cout<<x++%10<<" ";
            }
            puts("");
        }
    }
    return 0;
}