c++ 간단한 과제를 하는데 막혔네요.

#include <iostream>
using namespace std;
 
class car{
protected:
	double aversafe();
	double mileage();
	int safepoint1;
	int safepoint2;
	double distance;
	double liter;
};
 
double car::aversafe(){
	return (safepoint1+safepoint2)/2;
}
 
double car::mileage(){
	return distance/liter;
}
class safe : public car{
public:
	void input1();
};
 
void safe :: input1(){
	cout<<"1차 안전점수를 입력하세요:";
	cin>>safepoint1;
	cout<<"2차 안전점수를 입력하세요:";
	cin>>safepoint2;
};
 
class mileage : public car{
public:
	void inpuut();
};
 
void mileage :: inpuut(){
	cout<<"차의 주행거리를 입력하세요.(Km단위)";
	cin>>distance;
	cout<<"연료소모량을 입력하세요.(L단위)";
	cin>>liter;
};
 
 
class stand : public car{
	if(mileage()>15&&aversafe()>80)
	{cout<<"이 차는 합격입니다."<<endl;}
	else
	{cout<<"이 차는 불합격입니다."<<endl;}
	return 0;
};