Question

我无法返回动态分配的两个数组。我有一个读取数组大小的外部文件。（在我的情况下为20），当我使用动态分配的数组时，这就是使数组大小。

此外，一旦我返回它们，我当前的语法是否正确或是否有我应该改变的东西。

这是我的代码

int main (void)
{

    int size;
    int notFound = 0;
    int accountNumber = 0;
    int results;
    int * accountPtr = nullptr;
    double * balancePtr = nullptr;



    size = readFile(notFound, accountPtr, balancePtr);


    if (notFound == 0)
    {

     selectionSort(accountPtr, balancePtr, size);

        while  (accountNumber != -99)
            {
                cout << "Please Enter an Account Number (Type -99 to quit): ";
                cin >> accountNumber;

                if (accountNumber == -99)
                {
                    cout << "Goodbye!" << endl;
                }
                else
                {
                    results = binarySearch(accountPtr,accountNumber,size);
                    if ( results == -1)
                    {
                        cout << "That Account Number Does Not Exist." << endl;
                    }
                    else
                    {
                        cout << "\nAccount Number" << "\t\t" << "Account Balance" << endl;
                        cout << "-----------------------------------------------" << endl;
                        cout << fixed << setprecision(2) << accountPtr[results] << "\t\t\t" << balancePtr[results] << endl << endl;
                    }
                }


            }
    }

    return 0;
}

int readFile (int &notFound, int  *accountPtr, double  *balancePtr)

{
    int size;

    ifstream inputFile;

    inputFile.open("account.txt");

    if (inputFile.fail())
    {
     cout << "The File Account.TXT was not found." << endl;
     notFound = 1;
    }
    else
    {
        inputFile >> size;

        unique_ptr<int[]> accountPtr(new int[size]);
        unique_ptr<double[]> balancePtr(new double[size]);


        for(int i = 0; i < size; i++)
        {
            inputFile >> accountPtr[i] >> balancePtr[i];
        }

    }
    return size;
}

Answer 1

你按价值传递指针。调用代码中的指针变量不会被修改。除了传递值之外，在函数中你还要声明与正式参数同名的局部变量。

相反，您应该通过引用std::vector返回或传递。

C ++动态分配的内存返回数组

1 个答案: