问题描述
include 'stdafx.h'#include<iostream>#include<string>using namespace std;int main(){ struct Sales_Data {Sales_Data() = default;Sales_Data(const string &s) :bookNo(s) {}Sales_Data(const string &s, unsigned n, double p) :bookNo(s), units_sold(n), revenue(n*p) {}Sales_Data(istream &is);string isbn() const { return bookNo; }Sales_Data & combine(const Sales_Data&);double avg_price() const;//数据成员string bookNo;unsigned units_sold = 0;double revenue = 0; }; //在类的外部定义成员函数 double Sales_Data::avg_price()const {if (units_sold) return revenue / units_sold;else return 0; } Sales_Data add(const Sales_Data& data1, const Sales_Data& data2) {Sales_Data sum = data1;sum.combine(data2);return sum; } istream& read(istream &is, Sales_Data &item) {double price = 0;is >> item.bookNo >> ' ' >> item.units_sold;item.revenue = price*units_sold;return is; } ostream& print(ostream &os, Sales_Data &item) {os << item.bookNo >> ' ' << item.units_sold << ' ' << item.revenue;return os; } Sales_Data::Sales_Data(istream &is) {return read(is, *this); } Sales_Data& Sales_Data::combine(const Sales_Data& rhs) {units_sold += rhs.units_sold;revenue += rhs.renvenue;return *this; } Sales_Data t1; t1.Sales_Data('TheCatcherInRye', 3, 20.5); print(os, t1); return 0;}
问题解答
回答1：c++ 不能在函数里面定义函数。
