C 面向对象程序设计（第二版）课件 6.2.7 重载下标运算符

6.2.7重载下标运算符[]在此输入您的封面副标题重载下标运算符[]下标操作符[]通常用于访问数组元素。重载该运算符用于增强操作C++数组的功能。我们看下面的程序#include<iostream>#include<string.h>#include<stdlib.h>usingnamespacestd;classSales{public: voidInit(charch[]) { strcpy(name,ch); } char*GetName(){returnname;}

intdivisionTotals[5];//公司各个部门销售额private: charname[25];//公司名称};intmain(){inttotalSales=0,avgSales,i;Salescompany;company.Init("SweetToy");company.divisionTotals[0]=123;company.divisionTotals[1]=213;

company.divisionTotals[2]=324;company.divisionTotals[3]=351;company.divisionTotals[4]=289;cout<<company.GetName()<<endl;for(i=0;i<5;i++)cout<<company.divisionTotals[i]<<"\t";for(i=0;i<5;i++) totalSales+=company.divisionTotals[i];cout<<endl;cout<<"totalsalesis"<<totalSales<<endl;avgSales=totalSales/5;cout<<"averagesalesis"<<avgSales;}#include<iostream>#include<string.h>#include<stdlib.h>usingnamespacestd;classSales{public: voidInit(charch[]) { strcpy(name,ch); }

int&operator[](intsub);//数组下标运算符[]重载为类的友元函数 char*GetName(){returnname;}private: charname[25];//公司名称

intdivisionTotals[5];//公司各个部门销售额};int&Sales::operator[](intsub)//返回值是引用{ if(sub<0||sub>4)//判断下标是否越界 { cerr<<"数组下标越界."<<endl; abort(); } returndivisionTotals[sub];//返回下标为sub的部门销售额}intmain(){ inttotalSales=0,avgSales,i; Salescompany; company.Init("SweetToy");

company[0]=123;

//等价于：company.operator[](0)=123company[1]=213; company[2]=324; company[3]=351; company[4]=289; cout<<company.GetName()<<"'sdivisionsare:"<<endl; for(i=0;i<5;i++) cout<<company[i]<<"\t";//调用下标运算符重载函数

for(i=0;i<5;i++) totalSales+=company[i];cout<<endl;cout<<"totalsalesis"<<totalSales<<endl;avgSales=totalSales/5;cout<<"averagesalesis"<<avgSales;}程序运行结果：SweetToy'sdivisionsare:12