类模板，允许用户定义类型C++

我正在做一个关于使用向量的开放寻址哈希表的项目。该项目的一个方面是使用模板来允许用户定义矢量的类型。我已经实现了模板，如果我在编译之前创建一个对象，它可以工作，但是我不知道如何允许用户在运行时决定类型。

程序是面向对象的，类型必须传递到构造函数中。起初，我认为如果语句有效很简单，但是从那以后我了解到这不起作用。谁能帮我解决这个问题？谢谢

#include <iostream>
#include <string>
#include <vector>
using namespace std; 
template <class T>
class OpenHash 
{
private: 
vector <T> hashTab;
vector <int> emptyCheck;
int hashF(string);
public:
OpenHash(int);
int getVectorCap();
int addRecord (T);
int sizeHash();
int find(T);
int printHash();
int deleteEntry(T);
};
template <class T>
OpenHash<T>::OpenHash(int vecSize)
{
 hashTab.clear();
 hashTab.resize(vecSize);
 emptyCheck.resize(vecSize);
        for (int i=0; i < emptyCheck.capacity(); i++)   
        {
        emptyCheck.at(i) = 0;
        }
}
template <class T>
int OpenHash<T>::getVectorCap()
{
 int cap = hashTab.capacity();
 int capE = emptyCheck.capacity();
 cout << cap << capE;
return 0;
}
template <class T>
int OpenHash<T>::hashF (string key)
{
int ascii = 0, hasVal = 0;
    for (int i = 0; i < key.size(); i++)
        {
            ascii += key[i]; 
        }
hasVal = ascii % hashTab.capacity();
return hasVal;
}
template <class T>
int OpenHash<T>::addRecord(T key)
{
if (sizeHash() == emptyCheck.size())
{
    cout << "Your hash table is full cannot add any more records" << endl;
}
else
{
    bool findPos = false;
    for (int j=0; j<hashTab.capacity(); j++)
    {
        if (hashTab.at(j) == key)
        {
            cout << "Element ready exists in hashtable" << endl;
            return 0;
        }
    }
    int hashVal = hashF(key);
        for (int i=hashVal; i<emptyCheck.capacity(); i++)
        {
            if (emptyCheck.at(i) == 0)
            {
                hashTab.at(i) = key;
                emptyCheck.at(i) = 1;
                cout << "Element added at" << '[' << i << ']' <<  endl;
                findPos = true;
                return 0;
            }
            else 
            {
                cout << "Collision probing through..." << endl;
            }
        }
        if (findPos == false)
        {
            for (int x=0; x<emptyCheck.capacity(); x++)
            {
                if (emptyCheck.at(x) == 0)
                {
                    hashTab.at(x) = key;
                    emptyCheck.at(x) = 1;
                    cout << "Element added at" << '[' << x << ']' << endl;
                    findPos=true;
                    return 0; 
                }
            }
        cout <<  "Element could not be added" << endl;
        }

}   
return 1;
}
template <class T>
int OpenHash<T>::sizeHash()
{
int elementsFilled = 0;
    for (int i = 0; i<emptyCheck.capacity(); i++)
        {
            if (emptyCheck.at(i) != 0)
                {
                    elementsFilled++;
                }
        }
return elementsFilled;
}
template <class T>
int OpenHash<T>::find(T key)
{
int hashVal = hashF(key);
bool findLoop = false;

for (int i=hashVal; i < hashTab.capacity(); i++)
{
        if (hashTab.at(i) == key && emptyCheck.at(i) == 1)  
        {
            cout << "Element found at position: " << '[' << i << ']' << endl;
            cout << key << endl;
            findLoop = true;
            return 0;
        }   
        else
        {
            cout << "Element not found at position! Probing through..."  << endl;
            }

    }       
        if (findLoop == false)   
        {

            for (int j = 0; j < hashTab.capacity(); j++)
            {
                if (hashTab.at(j) == key && emptyCheck.at(j) != 0)
                {
                    cout << "Element found at position: " << '['  << j << ']' << endl;
                    cout << key << endl;
                    findLoop = true;
                    return 0;
                }
            }
        cout << "Entry not found" << endl;
        }
return 1;
}
template <class T>
int OpenHash<T>::deleteEntry(T toDel)
{
int hashVal = hashF(toDel);
bool foundDel = false;
    for (int i = hashVal; i<hashTab.capacity(); i++)
    {
        if (hashTab.at(i) == toDel)
        {
            emptyCheck.at(i) = 0;
            foundDel = true;
            cout << "Entry deleted!" << endl;
            return 0;
        }
    }
        if (foundDel == false)
        {
            for (int j=0; j<hashTab.capacity(); j++)
            {   
                if (hashTab.at(j) == toDel)
                {   
                    emptyCheck.at(j) = 0;
                    foundDel = true;
                    cout << "Entry deleted!" << endl;
                    return 0;
                }
            }
        cout << "The member to delete was not found" << endl;
        }   
return 1;
}
template <class T>
int OpenHash<T>::printHash()
{
if (sizeHash() == 0)
{
    cout << "No elements filled to print!" << endl; 
}
    for (int i=0; i<emptyCheck.capacity(); i++)
    {
        if (emptyCheck.at(i) != 0)
            {
                cout << "Record at:" << '[' << i << ']' <<  hashTab.at(i) << endl; 
            }   
    }
return 0;
}
int main () 
{
   cout << "Please input the size of your HashTable" << endl;
   int vecSize = 0;
   cin >> vecSize;
   OpenHash<string> newTable(vecSize);
bool menu = true;
char choice;
while (menu == true)    
{
    cout << "Welcome to the open address hash table program, please input your  choice:" << endl;
    cin >> choice;
        if (choice == 'a')
        {
            cout << "Please type in the record you wish to add:" <<   endl;
            string rec;
            getline(cin, rec);
        newTable.addRecord(rec);
        }
        if (choice == 's')
        {
            cout << "Number of elements filled: " << newTable.sizeHash()  << endl;
        }
        if (choice == 'f')
        {
            cout << "Please enter the string you wish to find" << endl;
            string key;
            getline(cin, key)
            newTable.find(key);
        }
        if (choice == 'p')
        {
            cout << "Printing table..." << endl;
            newTable.printHash();
        }
        if (choice == 'd')
        {
            cout << "Please input the item you wish to delete:" << endl;
            string toDel;
            getline(cin, toDel)
            newTable.deleteEntry(toDel);
        }
        if (choice == 'x')
        {
            cout << "Thankyou" << endl;
            menu = false;
        }
}
return 0;
}