C++ 模板类显示意外结果

Question

我已经定义了一个实现队列的模板类。

我插入 int 值：0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

当显示在屏幕队列内容中时，我会得到值：

0 1 2 3 4 5 6 7 10 11 12 13 14 15 16 代替。

我不明白为什么会有这种差异。请问您能帮帮我吗？

// 队列.h 文件

template <class T> class Queue
{
private:
    int numElements;
    T*  chain;
    int limit;


public:
    // Constructor
    Queue (int);

    void PutElement(T);
    T GetElement();
    void Print();
};



// Class Constructor.
template <class T> Queue<T>::Queue (int pNumElements)
{
numElements = pNumElements;
chain = new T[numElements];
limit = 0;
};



// Member functions.

template <class T> void Queue<T>::PutElement (T pElement)
{
if (limit < numElements)
    chain[limit++] = pElement;
else
    cout << "ERROR WHEN TRY TO INSERT A NEW ELEMENT: Queue is full.\n";
};




template <class T> T Queue<T>::GetElement()
{
T tempElement;

if (limit == 0) 
    {
    cout << "ERROR: Queue is empty\n";
    return NULL;
    }

tempElement = chain[0];

if (limit >= 2)
    for (int pos=1; pos < limit; pos++)
        chain[pos-1] = chain[pos]; 

limit--;

return tempElement;
};




template <class T> void Queue<T>::Print()
{
cout << "QUEUE CONTENTS: ";

for (int pos=0; pos<limit; pos++)
    if (pos < limit-1)
        cout << chain[pos] << ", ";
    else
        cout << chain[pos] << endl;
};


// main.cpp file:

#include <iostream.h>
#include "Queue.h"


void main()
{
cout << "\nint values QUEUE\n";
Queue <int> q1(15); // Max number of elements in queue is 15.
for (int aux=0; aux<17;aux++)
    q1.PutElement(aux);

q1.Print();

for (aux=1; aux<20;aux++)
    cout << "Queue element number " << aux << " is : " << q1.GetElement() <<     endl;
}"




// Screen result:

int values QUEUE
ERROR WHEN TRY TO INSERT A NEW ELEMENT: Queue is full.
ERROR WHEN TRY TO INSERT A NEW ELEMENT: Queue is full.
QUEUE CONTENTS: 0, 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16
Queue element number 1 is : 0
Queue element number 2 is : 1
Queue element number 3 is : 2
Queue element number 4 is : 3
Queue element number 5 is : 4
Queue element number 6 is : 5
Queue element number 7 is : 6
Queue element number 10 is : 7
Queue element number 11 is : 10
Queue element number 12 is : 11
Queue element number 13 is : 12
Queue element number 14 is : 13
Queue element number 15 is : 14
Queue element number 16 is : 15
Queue element number 17 is : 16
ERROR: Queue is empty
Queue element number 20 is : 0
ERROR: Queue is empty
Queue element number 21 is : 0
ERROR: Queue is empty
Queue element number 22 is : 0
ERROR: Queue is empty
Queue element number 23 is : 0"

Answer 1

也许我对你正在尝试做的事情感到困惑，但你没有插入值 0 到 14 的 int。在你的 main 函数中，你说就在那里

for (int aux=0; aux<17;aux++)
    q1.PutElement(aux);

这是输入值为 0 到 16 的整数...如您的输出所示。