c++并归排序

tips:模板没啥用，不过是为了实践下模板,也可以将数组作为成员变量，模板意义就有点了.

template 
class mergeSort
{
private:
    
public:
    mergeSort();
    ~mergeSort();
    void sort(std::vector &ans);
    void sort(std::vector &ans, std::vector &temp, int left, int right);
    void show(std::vector &ans);
    void merge(std::vector &ans, std::vector &temp, int left, int mid, int right);
};
template 
mergeSort::mergeSort()
{
    std::cout << "无参构造函数" << std::endl;
}
template 
mergeSort::~mergeSort()
{
    std::cout << "析构函数" << std::endl;
}
template 
void mergeSort::show(std::vector &ans)
{
    for (auto &x : ans)
        std::cout << x << " ";
    return;
}
template 
void mergeSort::sort(std::vector &ans)
{
    std::vector temp(ans.size(), 0);
    sort(ans, temp, 0, ans.size()-1);
    show(ans);
}
template 
void mergeSort::sort(std::vector &ans, std::vector &temp, int left, int right)
{
    if (left < right)
    {
        int mid = left+(right -left) / 2; //tips:与(left+right)/2一样，但是当数据量过于庞大时，left+right会溢出
        sort(ans, temp, left, mid);
        sort(ans, temp, mid + 1, right);
        merge(ans, temp, left, mid, right);
    }
    //return ;
}
template 
void mergeSort::merge(std::vector &ans, std::vector &temp, int left, int mid, int right)
{
    int i = left, j = mid + 1, t = 0;
    while (i <= mid && j <= right)
    {
        if (ans[i] <= ans[j])
            temp[t++] = ans[i++];
        else
            temp[t++] = ans[j++];
    }
    while (i <= mid)
        temp[t++] = ans[i++];
    while (j <= right)
        temp[t++] = ans[j++];
    t = 0;
    while (left <= right)
        ans[left++] = temp[t++];
}
//template