C++ 入门 类基础（2） 类的定义与实现分离

 1 #ifndef Number_H
 2 #define Number_H
 3 
 4 #include<iostream>
 5 using namespace std;
 6 
 7 //类接口声明
 8 class Number
 9 {
10 public:
11     Number();
12     Number(int value);
13     void rewrite(int value);
14     int read();
15 private:
16     int data;
17 };
18 #endif

 1 //A simple class that stored a data.
 2 //类接口与实现的分离
 3 
 4 #include "stdafx.h"
 5 #include"Number.h"
 6 
 7 //类实现
 8 Number::Number()
 9 {
10     data = 0;
11 }
12 
13 Number::Number(int value)
14 {
15     data = value;
16 }
17 
18 void Number::rewrite(int value)
19 {
20     data = value;
21 }
22 
23 int Number::read()
24 {
25     return data;
26 }
27 
28 int main()
29 {
30     Number num1 = Number();
31     cout << "default num1:  ";
32     cout << num1.read() << endl;
33     num1.rewrite(666);
34     cout << "changed num1:  ";
35     cout << num1.read() << endl;
36     Number num2 = Number(128);
37     cout << "setted num: 2  ";
38     cout << num2.read() << endl;
39 
40     system("pause");
41     return 0;
42 }