为啥零分啊

#include using namespace std;

int main() { double a;double c; cout << "请输入你的身高和体重" << endl; cin >> a >> c; if (c >= (a-100)*0.9 * 1.1) { cout << "fat" << endl; } else if (c <= (a - 100) * 0.9 * 0.9) { cout << "thin" << endl; } else if( (a - 100) * 0.9 * 0.9<c< (a - 100) * 0.9 * 1.1) { cout << "standard" << endl; } }