【练习】n阶数字三角形

#include <iostream>
using std::cin;
using std::cout;
using std::endl;
int main() {
    int n;
    cin >> n;
    
    for (int a=1; a<=n; a++){
        int k;

    if (a==1){
            k = n;
    }
        
        for (int b=1; b <= k; b++){
            cout << a;
            
            if (b < k){
                cout << " ";
            }
            else{
                cout << endl;
            }
        }
        
        k--;
    }
    
    return 0;
}