c++中删除struct数组中的元素

c++ deleting elements in a struct array

本文关键字：元素 数组 struct 删除 c++      更新时间：2023-10-16

下面的代码接受2个属性的用户输入并存储它。我一直未能找到一种方法来删除信息的属性，如果它被从市场上删除，提示用户输入要删除的属性id，也更新的属性详细信息，如改变出价提示用户输入属性id。我的老师建议我使用结构数组，到目前为止我已经做到了。

#include <iostream>                                           // takes users input and prints out output 
#include<conio.h>                                             // declares several useful library functions for performing "console input and output"
#include <stdio.h>                                            // compiler directive which stores standard input output 
using namespace std;                                          // defines the standard namespace 
struct Property                                               // declares the struct as Property 
{
   int ID[3];                                                // declare variable "ID" of data type interger to identify property ID 
   int Asking_Price;                                         // declare variable "Asking_Price" of data type interger to to identity the asking price for the property
   char Type[10];                                            // declare variable "Type" of data type char to identify the property type (detatched, semi-detatched, terraced, flat, commercial)
   char Address[20];                                         // declare variable "Address" of data type char to identify the property address
};
int main()  
{
   Property My_Property[2];                                      // declare the struct, the array and the number of array elements 
   for (int i=0;i<2;i++)                                         // for loop counts the number of properties from 1 to 5
   {
      cout << "n  Details of property ID " << i + 1 << " are :n"; // Prints out the property ID 
      cout << "t Enter the property asking price : ";             // Prompts the user to enter asking price fopr the property  
      cin >> My_Property[i].Asking_Price;                          // Takes users input and stores it in the array 
      cout << "t Please enter the property type: ";               //Prompts the user to enter the property type
      cin>>My_Property[i].Type;                                    //Takes users input and stores it in the array 
      cout << "t Please enter the property address : ";           //Prompts the user to enter the property address
      cin >> My_Property[i].Address;                               //Takes users input and stores it in the array 
   }
   for (int j = 0;j<2;j++)                                      // for loop counts the property information for all properties entered
   {
      cout << "n Information on property number " << j + 1 << " is :n";  //Prints out the stored property ID
      cout << "t Asking Price :" << My_Property[j].Asking_Price<<endl;  //Prints out the stored asking price for the property 
      cout << "t Property Type : " << My_Property[j].Type<<endl;            //Prints out the stored property type 
      cout << "t Address : " << My_Property[j].Address<<endl;           //Prints out the stored address for the property
   }
   for (int k=0;k<2;k++)    
   {
      cout << "n Please enter the property ID for the property you would like to delete : n ";
      cin>> My_Property[k].ID[3]; 
      if(My_Property[k].ID[3]>2)
      {
         cout<<"nn This property ID does not exist, press ENTER to try again: n";
      }
      else
      {
         //trying to figure out the delete code
      }
      _getch(); //read characters from screen`enter code here`
   }
}

实际上不能从数组中删除项，因为数组有固定的大小。从固定大小的容器中删除项的通常方法是将所有后续元素下移一个空格以覆盖不需要的项。

Property props[10];
int prop_count = 0;
// Fill props somehow, incrementing prop_count each time you add an item
std::cout << "n Please enter the property ID for the property you would like to delete : n ";
int to_delete;
std::cin >> to_delete;
for (int i = to_delete + 1; i < prop_count; ++to_delete) {
    props[i - 1] = props[i];
}
prop_count -= 1;

这或多或少是std::vector在掩护下的工作方式。

如果您不关心保持所有元素连续，您可以添加一些方法来将Property标记为已删除，但这往往会导致更复杂的代码。

最后，您可能应该使用一个可调整大小的容器，如std::vector，此时您可以调用std::vector::erase来擦除其中的项目。

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