C++模板类显示意外结果

C++ template class shows unexpected result

本文关键字：意外 结果 显示 C++      更新时间：2023-10-16

我定义了一个实现队列的模板类。

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

当在屏幕队列中显示内容时，我得到的值是：

0 1 2 3 4 5 6 7 10 11 12 13 14 15 16。

我不明白为什么会有这种区别。你能帮我吗？

//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 emptyn";
    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 QUEUEn";
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"

也许我对您试图做的事情感到困惑，但您没有插入值为0到14的int。在你的主要功能中，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…正如您的输出所示。

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