goods.h

一个不错库存管理算法

#include "string_con.h"
#include <string.h>
#include <stdlib.h>

class Goods{
	string name;
	int value;
public:
	Goods():name(""),value(0){}
	Goods(string &na,int va):name(na),value(va){}
	Goods(const Goods &g):name(g.name),value(g.value){}
	string GetName()const{
		return name;
	}
	int GetValue()const{
		return value;
	}
	void operator=(Goods &v){
		name=v.name;
		value=v.value;
	}
	Goods operator+(int cnt){//只有数量相加减才有意义
		int x=value+cnt;
		Goods temp(name,x);
		return temp;
	}
	Goods operator-(int cnt){
		int x=value-cnt;
		Goods temp(name,x);
		return temp;
	}
	int operator==(string &na){//只需要判断货物名称
		return name==na;
	}
	int operator!=(string &na){
		return name!=na;
	}
	int operator==(Goods &g){
		return name==g.name;
	}
	int operator!=(Goods &g){
		return name!=g.name;
	}
	friend istream& operator>>(istream& in, Goods &g);
	friend ostream& operator<<(ostream& out, Goods &g);
};

istream& operator>>(istream& in, Goods &g){
		char digit[20];
		int num;
		cout<<"货品名称："; in>>g.name;
		do {//容错控制
			cout<<"货品数量(输入不超过6位的数字字符，数值＞0)："; in>>digit;
			if (strlen(digit)>6) cout<<"对不起，数位太长，数据将溢出，请重输；"<<endl;
			else {
				num=atoi(digit); 
				if (num>0) {
					g.value=num; return in;
				}
				else cout<<"对不起，数据小于或等于0，请重输；"<<endl;
			}
		}while(1);
	}

ostream& operator<<(ostream& out, Goods &g){
		out<<"货品名称："<<g.name<<"   ";
		out<<"货品数量："<<g.value<<endl;
		return out;
	}