треугольная

#include <iostream>
using namespace std;


int main()
{
    int a[4][4] =
    {
        { 1,0,0,0 },
        { 1,0,0,0 },
        { 2,3,0,0 },
        { 3,0,1,0 },
    };
    int n = 4;
    bool b = true;
    bool q = false;
    for (int i = 0; i < n && b; i++)
    {
        for (int j = i + 1; j < n && b; j++)
        {

            if (a[i][j] != 0)
                b = false;
        }
    }
    if (b) {
        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j <= i; j++)
            {
                if (a[i][j] != 0)
                {
                    q = true;
                }
            }
        }
    }
    if (b && q) cout << "treugolnaya";
    else cout << "ne treugolnaya ";
    system("pause");
    return 0;
}