x==0也可以用!x表示

#include<iostream>
using namespace std;
int main()
{
    double x,y;
    cin>>x>>y;
    if(x>0 && y>0) cout<<"Q1"<<endl;
    else if(x<0 && y>0) cout<<"Q2"<<endl;
    else if(x<0 && y<0) cout<<"Q3"<<endl;
    else if(x>0 && y<0) cout<<"Q4"<<endl;
    else
    {
        if(x==0 && y==0) cout<<"Origem"<<endl;
        else if(y==0) cout<<"Eixo X"<<endl;
        else cout<<"Eixo Y"<<endl;
    }
    return 0;
}