（C ++）堆上的内存变为可访问/被删除
我在堆上遇到了一些问题。 看到我试图做多态，所以我分配了我使用的类的多态层次结构的基类的指针数组。 然而，我遇到了这样的问题，即当我将堆中的内存分配给指针数组中的指针时，此内存将在程序中稍后被删除。 指向动态分配内存的指针不会超出范围，但由于某些原因，指向指针的数据正变得无法访问/删除
#include "OverNightPackage.h"
#include "TwoDayPackage.h"
#include <iostream>
#include <string>
using namespace std;
int main()
{
const double overnightextracost = 1.45;
const double flatfee2day = 3.00;
const double costperoz = 1.55;
Package* packagelist[5] = {NULL};
int numpackages = 0;
bool sendanother = true;
string name;
string address;
string city;
string state;
string zip;
double weight;
cout << " Welcome to the package shippernn";
cout << " You will now enter your informationn";
cout << " Please enter your name ";
getline(cin, name);
cout << "n Please enter your address (ex 5228) n";
getline(cin, address);
cout << "n Please enter your city n";
getline(cin, city);
cout << "n Please enter your staten";
getline(cin, state);
cout << "n Please enter your 5 digit zipcoden";
getline(cin, zip);
Destination sender(name, address, city, state, zip);
while(sendanother && numpackages < 10)
{
sendanother = false;
numpackages++;
cout << "nn You will now enter the package recievers informationn";
cout << " Please enter recievers name ";
getline(cin, name);
cout << "n Please enter recievers address (ex 5228) n";
getline(cin, address);
cout << "n Please enter recievers city n";
getline(cin, city);
cout << "n Please enter recievers staten";
getline(cin, state);
cout << "n Please enter recievers 5 digit zipcoden";
getline(cin, zip);
Destination receiver(name, address, city, state, zip);
cout << "nn Please enter the weight of your package n";
cin >> weight;
cin.ignore();
char menuchoice;
cout << "nnn How would you like to ship your package?n";
cout << " Your options aren 1.) Regular Shipping -- " << costperoz << " cost per ouncen";
cout << " 2.) 2 Day Delivery -- " << flatfee2day << " flatfee addedn";
cout << " 3.) OverNight Delivery -- " << overnightextracost << " added per ouncen";
cin >> menuchoice;
if(menuchoice == '1')
{
//static Package * package = new Package(sender, receiver, weight, costperoz);
packagelist[numpackages] = new Package(sender, receiver, weight, costperoz);
}
if(menuchoice == '2')
{
//TwoDayPackage * package = new TwoDayPackage(sender, receiver, weight, costperoz, flatfee2day);
packagelist[numpackages] = new TwoDayPackage(sender, receiver, weight, costperoz, flatfee2day);
}
if(menuchoice == '3')
{
//static OverNightPackage * package = new OverNightPackage(sender, receiver, weight, costperoz, overnightextracost);
packagelist[numpackages] = new OverNightPackage(sender, receiver, weight, costperoz, overnightextracost);
}
cin.ignore();
cout << "nn Would you like to add another package? Y or Nnn";
cin >> menuchoice;
if(menuchoice == 'Y' || menuchoice == 'y')
sendanother = true;
else
sendanother = false;
cin.ignore();
}
cout << " nnn --- Shipment Information Below ---nn";
for(int i = 0; i < numpackages; i++)
{
if(packagelist[i] != NULL)
{
packagelist[i]->print();
cout << "n Shipment Price -- $" << packagelist[i]->calcCost() << "nn";
}
}
for(int i = 0; i < numpackages; i++)
delete packagelist[i];
system("pause");
return 0;
}
看看当我到达循环数组的最后部分并尝试使用polhymorphic函数时，这就是我开始获取内存访问冲突错误的地方（当我排除if（paackagelist [i]！= NULL）。将我在堆上分配给指针数组的数据推理出范围
与'范围'无关（不是在这种情况下确定你的意思）。
问题在于你放置numpackages++ 。 在将数组添加到数组之前将其增加，之后应该增加数组。
边界检查也是不正确的。 你的packagelist数组大小为5，但while循环表示numpackages < 10 。 这两个值应该是相同的，最好你应该声明一个常数来确保它们是相同的。
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