Question

我正在尝试将字符串值（“Appliance”，“Kitchenware”或“Tool”）添加到位于struct newItem中的C字符串数组“category [CATEGORY_SIZE]”，但是一旦用户尝试执行此操作，程序终止。如果我这样做不正确，有人可以解释为什么会这样以及如何正确存储字符串值吗？

#include <fstream>
#include <iostream>
#include <sstream> 
#include <cctype>
using namespace std;

//Array sizes
 const int CATEGORY_SIZE = 15, DATE_SIZE = 12;

//Declare structure for record
struct Item
{
  int SKU;
  string category[CATEGORY_SIZE];
  int quantity;
  double cost;
  string date[DATE_SIZE];
};

int main()
{
  //declare variables
  int answer;
  int cat;
  int month;
  string categoryChoice;
  string monthChoice;
  string theNumberString;
  string theNewNumberString;
  string fullDate;
  int dayChoice;
  int yearChoice;
  char anotherRecord;
  Item newItem; // to hold info about an item.
  fstream dataFile;

  fstream data("test.dat", ios::out | ios::binary);

  cout << "This program allows you to store inventory data for appliances, kitchenware,  
           and tools in a file.";

while (true)
{

cout << "What would you like to do? :\n\n";
cout << "1. Add new records to the file\n";
cout << "2. Display a record in the file\n";
cout << "3. Change any record in the file\n";
cout << "4. Display total wholesale value of a particular item inventory.\n";
cout << "5. Display total wholesale value of a particular category inventory.\n";
cout << "6. Display total quantity of all items in the inventory." << endl;
cout << "Please enter a number[1-6] or enter 0 to quit program: ";
cin >> answer;

if (answer == 0)
{
  return 0;
}

if (answer < 0 || answer > 6)
  cout << "That is not a valid response, please try again. ";

if (answer == 1)
{
  while (true)
  {
    cout << "Enter the following data about an item: \n\n";
    cout << "SKU Number (Stock Keeping Unit Number): ";
    cin >> newItem.SKU;
    cin.ignore(); //Skip over the remaining newline.

    while (true)
    {
      cout << "Please enter what category the item falls in : \n";
      cout << "1. Appliance \n" "2. Kitchenware \n"  "3. Tool: \n" << endl;
      cout << "Please enter a choice [1-3]: ";
      cin >> cat ;

      if (cat < 1 || cat > 3)
        cout << "Invalid choice. Please select again." << endl;
      else if (cat == 1)
      {
        newItem.category[CATEGORY_SIZE] = "Appliance";
        break;
      }
      else if (cat == 2)
      {
        newItem.category[CATEGORY_SIZE] = "Kitchenware";
        break;
      }
      else if (cat == 3)
      {
        newItem.category[CATEGORY_SIZE] = "Tool";
        cout << newItem.category[CATEGORY_SIZE];
        break;
      }

      }
     }
    }

Answer 1

newItem.category[CATEGORY_SIZE] = "Appliance";

（同样）：您有未定义的行为。您正在访问数组越界，因为索引属于[0, size)范围。使用std::vector以及push_back或emplace_back（取决于C ++ 11支持）：

std::vector<std::string> category; //you can construct this with an initial size
...
newItem.category.push_back("Appliance");

在Structure C ++中添加值C-string

1 个答案: