C ++ - 有序ArrayList

Question

我有一个有序的arrayList。在1,2,3,4,5,6中订购元件的地方。 此时推送功能不起作用。它会插入一个元素，但是有一个我无法弄清楚的问题。插入一个递增的数字后推送将起作用...所以像1,2,3,4,5但是一旦插入像这样的5,2,4,3,2,1就无法工作。 任何人都可以帮我这个吗？

这是我的代码：

初始化

template <class Datatype>
//--------------------------------------------------------------------------------------------
//  Class: OrderedArray.
//--------------------------------------------------------------------------------------------
class OrderedArray
{
    //--------------------------------------------------------------------------------------------
    //  Member Variables.
    //--------------------------------------------------------------------------------------------
private:
    Datatype* m_array;
    int size;
    int g_size;
    int num_elements;
    //---------------------------------------------------------------------------------------
    //  Name:            Print Function:
    //  Description:     To print out all elemenst in the Array.
    //---------------------------------------------------------------------------------------
    void print()
    {
        for(int i=0;i< size;i++)
        {
            cout << "Position: " <<m_array[i]<<endl;
        }
    }

    //---------------------------------------------------------------------------------------
    //  Name:           Resize Function:
    //  Description:    To resize the Array.
    //---------------------------------------------------------------------------------------
    void Resize(int p_size)//resizes the array to the size of p_size
    {
        if(p_size < 0)//checks if new size is less than 0
        {
            cout << "ERROR! Size of an array can not be less than 0!" << endl;
        }
        else//else its ok to continue
        {
            Datatype* newArray = new Datatype[p_size];//creates a pointer newArray that points at a new array
            if(newArray == 0)
                return;

            int min;

            if(p_size < m_size)//checks the if the new array is smaller than the old one
                min = p_size;
            else//else its going to be bigger
                min = m_size;

            int index;
            int temp = num_elements;//puts num_elements into a temporary variable called temp
            num_elements = 0;//num_elements is set to 0
            for(index = 0; index < min; index++)
            {
                newArray[index] = m_array[index];//places everything from the old array into the new array that will fit.
                if(num_elements < temp)//if the num_elements is less than temp(the original num_elements)
                {
                    num_elements++;//increment num_elements. This will keep incrementing to create the new num_elements based the number of elements cut off in the resize
                }
            }
            m_size = p_size;//sets the old size to be equal to the new size

            if(m_array != 0)
                delete[] m_array;//deletes the old array
            m_array = newArray;//makes m_array point at the new array
            newArray = 0;//makes newArray a null pointer
        }
    }


    //---------------------------------------------------------------------------------------
// Name:             Push
// Description:      
//---------------------------------------------------------------------------------------
void push(Datatype p_item)
{
    if(num_elements == size)//checks if the array is full and needs to be resized
    {
        Resize(size + g_size);//calls the resize function
    }

    int pos = num_elements;
    for(int x=0;x<num_elements;x++)
    {
        if(p_item < m_array[x])
        pos=x;
        break;
    }

    //loops through the array from high to low moving all values to the right
    //to make space for the passed in value until it gets to the right place
    for(int index = num_elements; index >= pos; index--)
    {
        m_array[index] = m_array[index-1];//moves the values to the right
    }
        m_array[pos] = p_item;//the passed in value is positioned into its ordered position
        num_elements++;

    cout<< "Num Elements " << num_elements;
    cout<< "Size " <<size;
}

Answer 1

我想我找到了问题的开始：

for(int x=0;x<num_elements;x++)
{
    if(p_item < m_array[x])
        pos=x;
}

你的pos将始终始终位于数组的末尾（假设数组已正确排序到该点）。添加break语句，让您的循环知道何时应该停止为pos分配越来越大的值

for(int x=0;x<num_elements;x++)
{
    if(p_item < m_array[x])
    {
        pos=x;
        break;
    }
}

---

您的代码也有其他一些问题，例如

for(int index = num_elements; index > pos; index--)
{
    m_array[index] = m_array[index+1];//moves the values to the right
}

实际上移动了左边的值。将作业更改为

for(int index = num_elements; index > pos; index--)
{
    m_array[index] = m_array[index-1];//moves the values to the right
}