// A simple inventory program using a struct to store data
// in an array.
#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include <sstream>
using namespace std;
// define a data structure
struct InventoryRecord
{
string name; // inventory item name
int qty; // how many are in stock
double value; // the value
};
// const for the max size of the record array
const int MAX_SIZE = 9;
// function prototypes
void addData(InventoryRecord list[], int& size);
void dispData(const InventoryRecord list[], int size);
void remData( const InventoryRecord list[], int size);
void saveFile(const InventoryRecord list[], int size);
void openFile(InventoryRecord list[], int& size);
char getMenuResponse();
int main(int argc, char *argv[])
{
InventoryRecord recList[MAX_SIZE];
int numOfRecs = 0;
bool run = true;
do
{
cout << "Hero's Inventory - " << numOfRecs << " items in your bag" << endl;
switch ( getMenuResponse() )
{
case 'A': addData(recList, numOfRecs); break;
case 'D': dispData(recList, numOfRecs); break;
case 'R': remData(recList, numOfRecs); break;
case 'O': openFile(recList, numOfRecs); break;
case 'S': saveFile(recList, numOfRecs); break;
case 'Q': run = false; break;
default : cout << "That is NOT a valid choice" << endl;
}
} while (run);
cout << endl << "Program Terminated" << endl;
// system("PAUSE"); // Program exits immediatly upon "Quit" if commented out
return EXIT_SUCCESS;
}
// Task: Allow data entry of one inventory item
// Accepts: References to the inventory array and its size
// Returns: Nothing
// Modifies: The array and size 'actual parameter'
// NOTE: Could be modified to allow entry of more than one item
void addData(InventoryRecord list[], int& size)
{
InventoryRecord tmp; // declare a temp item that we will load before putting in the array
char response;
char str[256]; // needed for cin.getline; we are going to use a char array
if (size < MAX_SIZE) {
system("cls");
cout << "Please enter 10 items helpful to your quest! " << endl;
cout << "Enter item: " << endl << endl;
cout << "Name: ";
// Get up to 256 characters from the keyboard including white space.
// Stop reading if encounter the \n first. If there's any chance of
// more than 256 characters you will have to clean up cin with
// cin.ignore before the next input.
cin.getline(str, 256, '\n'); // for char arrays; different from the other getline
tmp.name = str;
cout << "Quantity: ";
cin >> tmp.qty;
cout << "Value: ";
cin >> tmp.value;
cout << endl;
// see if this record should be added to the array
cout << "Add to inventory? (y/n) ";
cin >> response;
if (toupper(response) == 'Y')
list[size++] = tmp;
} else {
cout << "Inventory is full; cannot enter more units." << endl;
system("pause");
}
system("cls");
}
void dispData(const InventoryRecord list[], int size)
{
system("cls");
double cost = 0;
if(size < 1) {
cout << "Nothing to display" << endl;
} else {
cout << "All Items in your Bag" << endl << endl;
cout << fixed << setprecision(2);
cout << "Item Name Qty Value" << endl;
cout << "~~~~~~~~~~~~~~~~~~" << endl;
cout << left;
for (int i = 0; i < size; i++) {
cout << setw(21) << list[i].name << right
<< setw(4) << list[i].qty
<< setw(10) << list[i].value << left << endl;
cost = cost + list[i].value * list[i].qty;
}
cout << "~~~~~~~~~~~~~~~~~~~" << endl;
cout << right << setw(3) << size;
cout << " items listed";
cout << right << setw(19) << cost << endl << endl;
}
system("PAUSE");
system("cls");
}
void remData(const InventoryRecord list[], int size) {
system("cls");
cout <<"Enter Item you wish to remove from your inventory: " << endl;// This is being displayed so user can see items in the inventory
double cost = 0;
if(size < 1) {
cout << "Nothing to display" << endl;
} else {
cout << "All Items in your Bag" << endl << endl;
cout << fixed << setprecision(2);
cout << "Item Name Qty Value" << endl;// It is not displaying right the alignment is off
cout << "~~~~~~~~~~~~~~~~~~" << endl;
cout <<"Item Name: ";/* from here I do not know what to do! What I want is have use type the item name they want removed
also display an error if they enter an item wrong*/
cout << left;
for (int i = 0; i < size; i++) {
cout << setw(21) << list[i].name << right
<< setw(4) << list[i].qty
<< setw(10) << list[i].value << left << endl;
cost = cost + list[i].value * list[i].qty;
}
cout << "~~~~~~~~~~~~~~~~~~~" << endl;
cout << right << setw(3) << size;
cout << " items listed";
cout << right << setw(19) << cost << endl << endl;
}}
// Save records to disc
void saveFile(const InventoryRecord list[], int size) {
ofstream outfi("Inventory.txt");
// make sure the file stream is open before doing IO
if (!outfi.fail()) {
system("cls");
cout << "Saving inventory to the disc ";
for(int i = 0; i < size; i++) {
outfi << list[i].name << ';'
<< list[i].qty << ';'
<< list[i].value;
// Start a new line after all but the last record
// Simplifies reading the file as EOF is at end of last line
if (i < size-1) outfi << endl;
}
cout << endl << size << " records writen to the disc." << endl;
outfi.close();
system("PAUSE");
system("cls");
}
else {
cout << "ERROR: problem with file" << endl;
system("PAUSE");
system("cls");
}
}
// Open file and load array
void openFile(InventoryRecord list[], int& size)
{
ifstream infi("Inventory.txt");
string str;
stringstream strstrm;
// make sure the file stream is open before doing IO
if (!infi.fail()) {
system("cls");
cout << "Reading inventory from the disc ";
size = 0; // overwrite any existing records
while(!infi.eof() && size < MAX_SIZE) {
// get and store the name
getline(infi, str, ';');
list[size].name = str;
// get, convert and store the quantity
getline(infi, str, ';');
strstrm.str(""); strstrm.clear(); // empty and clear the stringstream
strstrm << str;
strstrm >> list[size].qty;
// get, convert and store the cost
getline(infi, str);
strstrm.str(""); strstrm.clear(); // empty and clear the stringstream
strstrm << str;
strstrm >> list[size++].value;
}
cout << endl << size << " records read from the disc." << endl;
system("PAUSE");
system("cls");
}
else { // something went wrong with opening the file
cout << "ERROR: problem with file" << endl;
system("PAUSE");
system("cls");
}
}
char getMenuResponse()
// Task: Put the menu on screen and get a response
// Accepts: Nothing
// Returns: The users response
// Modifies: Nothing
// NOTE: Characters are far more intuitive at the command
// line than numbers; avoid using numbers.
{
char response;
cout << endl << "Make your selection" << endl
<< "(A)dd Items, (D)isplay Items, (R)emove items, (O)pen File, (S)ave File, (Q)uit" << endl
<< "> ";
cin >> response;
cin.ignore(256, '\n');
// clean-up up to 256 chars including the delimiter specified (\n, the endl)
// OR stop when the \n is encountered after removing it.
return toupper(response);
}
答案 0 :(得分：0)
基本上有两种方法可以删除元素，最简单的方法是将要删除的元素与最后一个元素交换并调整列表大小：
void deleteElem(Data[] list, int & listLength, int ix) {
if (ix < listLength - 1) {
list[ix] = list[listLength - 1];
}
--listLength;
}
第二个解决方案是在删除左边的元素之后进行memmove：
void deleteElem(Data[] list, int & listLength, int ix) {
memmove(list[ix], list[ix + 1], (listLength - ix - 1) * sizeof(Data));
--listLength;
}
编辑：memmove的长度有误，总是一样的。您应该阅读documentation。
答案 1 :(得分：0)
要从广告资源中删除元素，只需将删除的元素后面的所有元素向前移动一个位置即可。完成后，您还需要将冗长减少一个。例如，要删除数组index中位置array的元素，其中包含当前length元素，您可以使用
if (index < length) {
std::copy(array + index + 1, array + length, array + index);
++length;
}