Question

在翻阅我的作业时，我遇到了一个我无法弄清楚的错误。我已经阅读并玩过它，但我无法弄清楚我做错了什么。

用户输入int指针数组，然后代码应该是数组大小的两倍，并使用0填充新元素。问题是新元素不是0。我做错了什么，打印的这些数字是什么，地址？

输出：

Enter array size: 3
Enter Element 0: 10
Enter Element 1: 11
Enter Element 2: 12

Entered Array:
Element 0/3 is 10
Element 1/3 is 11
Element 2/3 is 12

Resized Array:
Element 0/6 is 10
Element 1/6 is 11
Element 2/6 is 12
Element 3/6 is -33686019
Element 4/6 is 1196933248
Element 5/6 is 201354124

Press any key to continue . . .

代码：

#include <iostream>
#include <string>

using namespace std;

int *createArray(int size)
{
    int *newArray;

    newArray = new int[size];

    for( int i = 0; i < size; i++){
        cout << "Enter Element " << i << ": ";
        cin >> newArray[i];
    }
    return newArray;
}

int *dblArraySize ( int *myArray, int& size)
{
    int *newArray;

    newArray = new int[size*2];

    for (int i = 0; i < size; i++)
        newArray[i] = myArray[i];

    for (int i = size; i < size*2; i++){
        newArray[i] = 0;
    }

    size = size*2;
    return newArray;         
}

void displayArray(int *anArray, int size, string msg)
{   
    cout <<endl << endl << msg;
    for (int i = 0; i<size;i++){
        cout << endl << "Element " << i << "/" << size << " is " << anArray[i];
    }
}

int main ()
{
    int size,
        *mainArray;

    cout << "Enter array size: ";
    cin >> size;
    mainArray = createArray(size);

    displayArray(mainArray,size, "Entered Array:");

    dblArraySize(mainArray,size);

    displayArray(mainArray,size, "Resized Array:");
}

Answer 1

问题是你从dblArraySize返回newArray，但从不使用它。你永远不会修改mainArray

 dblArraySize(mainArray,size);

应该是：

 mainArray = dblArraySize(mainArray,size);

另请注意：您忘记释放原始阵列的内存。

C ++在调整大小的动态数组中填充新元素

1 个答案: