初学者关于类的问题

我是初学者，自学，编了一段代码，但是GUN老是报错，那位高手，帮忙看下
1    #include <iostream>
2   
3    class Tricycle
4    {
5    public:
6        int getSpeed() ;
7        void setSpeed(int speed);
8        void pedal();
9        void break();
10    private:
11        int speed;
12    };
13   
14    int Tricycle::getSpeed()
15    {
16        return speed;
17    }
18
19    void Tricycle::setSpeed(int speed)
20    {
21        if(newSpeed >= 0)
22        {
23            speed = newSpeed ;
24        }
25    }
26
27    void Tricycle::pedal()
28    {
29        setSpeed(speed + 1);
30        std::cout<<"\nPedaling;tricycle speed"<<speed<<"mph\n";
31    }
32   
33    void Tricycle::break()
34    {
35        setSpeed(speed - 1);
36        std::cout<<"\nBreaking;tricycle speed"<<speed<<'mph\n";
37    }
38
39    int main()
40    {
41        Tricycle man;
42        man .setSpeed(5);
43        man .pedal();
44        man .pedal();
45        man .pedal();
46        man .break();
47        man .break();
48        return 0;
49    }
50

报错在9，21，33，36，46，47行，谁帮忙看一下？？