#include <fstream.h>
void main()
{
//悄喊 假如我们已经在test_file.txt中存有了“Hello”的内容
ifstream File("test_file.txt")
char arr[10]
File.read(arr,10)
// 由于Hello占5个字符，因此这里将返回5
cout <<File.tellg() <<endl
File.close()
}
tellp() —— 与tellg()有同样的功能，但它用于写文件时。总而言之：当我们读取一个文件，并要知道内置指针的当前位置时，应该使用tellg()；当我们启档野写入一个文件，并要知道内置指针的当前位置时，应该使用tellp(). 由于此函数的用法与tellg()完全一样
#include<iostream>#include<fstream>
#include<string>
#include<list>
#include<sstream>
#include<Windows.h>
using namespace std
class Goods{
public:
Goods(string Id="", string Name="", double Price=0, int Number=0) :
id(Id), name(Name), price(Price), number(Number){}
string GetName(){ return name}
string GetId(){ return id}
double GetPrice(){ return price}
int GetNumber(){ return number}
private:
string id
string name
double price
int number
}
class Storehouse{
public:
Storehouse()
void DeleteSize()
void AddSize()
void AddSize(Goods)
void FindName()
void FindId()
void ShowLessNumber()
void ShowAllGoods()
list<Goods>::iterator Begin(){ return goodsList.begin()}
list<Goods>::iterator End(){ return goodsList.end()}
private:
bool CheckId(string)
bool CheckName(string)
list<Goods>goodsList
void ShowGoods(list<Goods>::iterator)
}
Storehouse::Storehouse(){}
void Storehouse::ShowGoods(list<Goods>::iterator iter){
cout <<"编号：" <<iter->GetId() <<endl
cout <<"名称：" <<iter->GetName() <<endl
cout <<"单价：" <<iter->GetPrice() <<厅团 endl
cout <<"数量：" <<iter->GetNumber() <<endl
}
void Storehouse::DeleteSize(){
string name
cout <<"请输入需要删除的货物的名称" <<endl
cin >>name
list<Goods>::iterator beg = goodsList.begin()
list<Goods>::iterator end = goodsList.end()
while (beg!= end){
if (beg->GetName() == name)
break
beg++
}
if (beg == end){
cout <<"你输入的货物不存在" <<endl
}
else{
goodsList.erase(beg)
cout <<"已成功删除该货物信息" <<endl
}
}
void Storehouse::AddSize(){
string id, name
double price
int number
cout <<"添加的货物编号是" <<endl
cin >>id
while (1){
if (CheckId(id))
break
else{
cout <<"携敬输入的货物编号已存在,需辩伏慎重新输入编号："
cin >>id
}
}
cout <<"货物名称是:" <<endl
cin >>name
while (1){
if (CheckName(name))
break
else{
cout <<"输入的货物名称已存在，需重新输入名称"
cin >>name
}
}
cout <<"货物单价是" <<endl
cin >>price
cout <<"货物数量是:" <<endl
cin >>number
Goods goods(id, name, price, number)
goodsList.insert(goodsList.end(), goods)
}
void Storehouse::AddSize(Goods goods){
goodsList.insert(goodsList.end(),goods)
}
void Storehouse::FindId(){
string id
cout <<"要查询的货物编号是：" <<endl
cin >>id
list<Goods>::iterator beg = goodsList.begin()
list<Goods>::iterator end = goodsList.end()
while (beg != end){
if (beg->GetId() == id)
break
beg++
}
if (beg == end)
{
cout <<"该编号货物不存在"
}
else{
cout <<"该货物信息如下：" <<endl
ShowGoods(beg)
}
}
void Storehouse::FindName(){
string name
cout <<"要查询的货物的名称是" <<endl
cin >>name
list<Goods>::iterator beg = goodsList.begin()
list<Goods>::iterator end = goodsList.end()
while (beg != end){
if (beg->GetName() == name)
break
beg++
}
if (beg == end){
cout <<"该名称的货物不存在" <<endl
}
else
ShowGoods(beg)
}
void Storehouse::ShowLessNumber(){
int number
cout <<"要显示数量少于多少件的货物?" <<endl
cin >>number
list<Goods>::iterator beg = goodsList.begin()
list<Goods>::iterator end = goodsList.end()
cout <<"数量少于" <<number <<"个的商品分别有:" <<endl
while (beg != end){
if (beg->GetNumber() <number){
ShowGoods(beg)
cout <<endl
}
beg++
}
}
void Storehouse::ShowAllGoods(){
list<Goods>::iterator beg = goodsList.begin()
list<Goods>::iterator end = goodsList.end()
int i = 0
cout <<"所有货物的信息:" <<endl
while (beg != end){
i++
cout <<"第" <<i <<"个货物信息：" <<endl
ShowGoods(beg)
cout <<endl
beg++
}
}
bool Storehouse::CheckId(string id){
list<Goods>::iterator beg = goodsList.begin()
list<Goods>::iterator end = goodsList.end()
for (beg != endbeg++){
if (beg->GetId() == id)
break
}
return beg == end
}
bool Storehouse::CheckName(string name){
list<Goods>::iterator beg = goodsList.begin()
list<Goods>::iterator end = goodsList.end()
for (beg != endbeg++){
if (beg->GetName() == name)
break
}
return beg == end
}
void ReadGoods(Storehouse&store){
system("cls")
ifstream inNotes("保存记录.txt", ios::_Noreplace)
string choice
string textName
getline(inNotes, textName)
if (textName.empty()){
cout <<"输入2读取制定路径文件，输入其他直接进入 *** 作页面" <<endl
getline(cin, choice)
}
else{
cout <<"检查到你上次数据保存到" <<textName <<endl
cout <<"输入1读取该文件的内容,输入2读取指定路径文件，输入其他直接进入 *** 作页面" <<endl
getline(cin, choice)
}
if (choice != "1"&&choice!="2")
return
if (choice == "2")
{
cout <<"输入读取路径:"
getline(cin, textName)
}
if (choice == "1"&&textName.empty())
return
ifstream inGoods(textName,ios::_Nocreate)
if (!inGoods.is_open()){
cout <<"无法读取该路径文件,请检查路径是否有误,\n按回车键继续..." <<endl
getline(cin,choice)
ReadGoods(store)
return
}
string text
string name
string id
double price
int number
while (getline(inGoods, text)){
stringstream ss(text)
for (int i = 0i <4i++)
switch (i){
case 0:ss >>idbreak
case 1:ss >>namebreak
case 2:ss >>pricebreak
case 3:ss >>numberbreak
}
Goods goods(id, name, price, number)
store.AddSize(goods)
}
}
void SaveGoods(Storehouse store){
string pathName
cout <<"输入需要保存的路径:"
cin.clear()
cin.sync()
getline(cin, pathName)
ofstream out(pathName)
list<Goods>::iterator beg = store.Begin()
list<Goods>::iterator end = store.End()
while (beg != end){
out <<beg->GetId() <<" " <<beg->GetName() <<" " <<beg->GetPrice() <<" " <<beg->GetNumber() <<endl
beg++
}
ofstream outNotes("保存记录.txt", ios::trunc)
outNotes <<pathName
}
void ToBeEnd(Storehouse&store){
system("cls")
int i
cout <<"1.保存,2.不保存" <<endl
while (1){
cin.clear()
cin.sync()
cin >>i
switch (i)
{
case 1:SaveGoods(store)return
case 2:return
default:cout <<"输入有误,重新输入1或者2，选择是否保存数据" <<endlbreak
}
}
}
void Reback(){
cout <<"\n\n按下回车键返回..." <<endl
string s
cin.clear()
cin.sync()
getline(cin, s)
}
void main(){
bool toBeEnd = false
int i
string s
Storehouse house
ReadGoods(house)
while (1){
system("cls")
cout <<"1.添加货物, 2.删除货物, 3.按编号查询货物, 4.按名称查询货物, \n"
cout<<"5.输出数量不足的货物, 6.显示所有货物信息, 7退出" <<endl
cin >>i
system("cls")
switch (i){
case 1:house.AddSize()break
case 2:house.DeleteSize()break
case 3:house.FindId()break
case 4:house.FindName()break
case 5:house.ShowLessNumber() break
case 6:house.ShowAllGoods()break
case 7:toBeEnd = truebreak
default:cout <<"请输入1至7的数字选择 *** 作\n"break
}
if (toBeEnd)
break
Reback()
}
ToBeEnd(house)
}
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