C/C++: 操作符重载案例

1 案例：+ ,- ,++, --

// 操作符重载.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"


class Fraction
{
public:
  Fraction(): num(2),den(1){
    //默认值
  }

  Fraction(int n,int d):num(n),den(d){

  }

  ~Fraction();


  Fraction operator + (const Fraction &other){
    Fraction result;
    result.den = den * other.den;//分母相乘
    result.num = num * other.den + den * other.num;//分子交叉相乘
    return result;
  }

  

  Fraction operator - (const Fraction &other){
    Fraction result;
    result.den = den * other.den;//分母相乘
    result.num = num * other.den - den * other.num;//分子交叉相减
    return result;
  }

  Fraction operator ++ (){
    Fraction result;
    result.den = den ;//分母不变
    result.num = num + den;//分子加上分母
    return result;
  }

  Fraction operator -- (){
    Fraction result;
    result.den = den ;//分母不变
    result.num = num - den;//分子减去分母
    return result;
  }

public:
  int num;
  int den;

};

Fraction::~Fraction()
{

}


int _tmain(int argc, _TCHAR* argv[])
{
  Fraction *f1 = new Fraction(5,6);
  Fraction f2(2,3);
  Fraction f3(3,5);
  Fraction f4 = f2 + f3;
  Fraction f5 = f2 - f3;
  Fraction f6 = f5--;
  Fraction f7 = f5++;

  return 0;
}      

2 案例: []

 1 简要说明: 

   创建2个类，Student和StudentData类，

   Student里有id，

   StudentData里使用操作符[]获取Student，然后输出id

  2 代码如下:

// 重载2.cpp : 定义控制台应用程序的入口点。
// [] 重载案例

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>


class Student
{
public:
  Student(){}
  Student(int id):id(id){}

  ~Student(){}

  void showId(){
    printf("student id:%d\n",id);
  }

private:
  int id; 
};


class StudentData
{
public:
  StudentData(int size);
  ~StudentData();

  void addStudent(Student *stu){
    *(_stu_buf + count ) = *stu;
    count++;
  }

  Student operator[] (int id){
    return _stu_buf[id];
  }
private:
  int count;
  Student *_stu_buf;
};

StudentData::StudentData(int size)
{
  count = 0;
  _stu_buf = (Student *)malloc(size * sizeof(Student)); 
}

StudentData::~StudentData()
{

}


int _tmain(int argc, _TCHAR* argv[])
{
  //定义student集合
  StudentData data(10);

  //批量创建student
  for (int i = 0; i < 10; i++)
  {
    Student stu(i);
    data.addStudent(&stu);
  }

  for (int i = 0; i < 10; i++)
  {
    // 显示id
    data[i].showId();
  }


  while (true)
  {

  }

  return 0;
}      

     3 效果如下