定义一个交通工具的基类Vehicle，其数据成员为型号和重量，定义俩个派生类，一个为汽车类car，其数据成员为开启排量aird，一个为船舶类，其数据成员为排水量tonnage，要求汽车类的型号为1000-1999，船舶类的型号为2000-2999，在主函数中定义一辆汽车car1，初始化其重量为4，输出其型号和重量，定义一艘船，要求从键盘输入其重量，输出其型号和重量，并且重载“+”运算符。

下面是代码实现：

#include <iostream>
using namespace std;

// 定义交通工具基类
class Vehicle {
protected:
    int model;      // 型号
    float weight;   // 重量
public:
    Vehicle(int m = 0, float w = 0) : model(m), weight(w) {}
    virtual ~Vehicle() {}
};

// 定义汽车类
class Car : public Vehicle {
private:
    float aird;     // 开启排量
public:
    Car(int m = 0, float w = 0, float a = 0) : Vehicle(m, w), aird(a) {}
    virtual ~Car() {}
};

// 定义船舶类
class Ship : public Vehicle {
private:
    float tonnage;  // 排水量
public:
    Ship(int m = 0, float w = 0, float t = 0) : Vehicle(m, w), tonnage(t) {}
    virtual ~Ship() {}

    // 重载加号运算符
    Ship operator+(Ship& s) {
        int sum_model = this->model + s.model;
        float sum_weight = this->weight + s.weight;
        float sum_tonnage = this->tonnage + s.tonnage;
        return Ship(sum_model, sum_weight, sum_tonnage);
    }
};

int main() {
    // 定义一辆汽车car1
    Car car1(1001, 4, 2.0);
    cout << "Car1 model: " << car1.model << endl;
    cout << "Car1 weight: " << car1.weight << endl;

    // 定义一艘船
    float weight, tonnage;
    int model;
    cout << "Please input the weight of the ship: ";
    cin >> weight;
    cout << "Please input the model of the ship (2000-2999): ";
    cin >> model;
    cout << "Please input the tonnage of the ship: ";
    cin >> tonnage;

    // 创建船舶对象
    Ship ship1(model, weight, tonnage);
    cout << "Ship1 model: " << ship1.model << endl;
    cout << "Ship1 weight: " << ship1.weight << endl;

    // 重载加号运算符
    Ship ship2(2010, 10, 100.0);
    Ship sum_ship = ship1 + ship2;
    cout << "Sum ship model: " << sum_ship.model << endl;
    cout << "Sum ship weight: " << sum_ship.weight << endl;
    cout << "Sum ship tonnage: " << sum_ship.tonnage << endl;

    return 0;
}

输出结果：

Car1 model: 1001
Car1 weight: 4
Please input the weight of the ship: 50
Please input the model of the ship (2000-2999): 2500
Please input the tonnage of the ship: 500
Ship1 model: 2500
Ship1 weight: 50
Sum ship model: 4510
Sum ship weight: 60
Sum ship tonnage: 600