未调用继承的重写方法

为什么账户类操作方法中的depositmoney()方法调用账户类的depositmoney()，而不是Sav_account类的方法？对depositmoney()方法的直接调用调用了子类的方法，这是显而易见的。但无法理解为什么operations()的间接调用没有给出预期的结果。

#include<iostream>
#include<conio.h>
#include<string>
using namespace std;
int temp = 0;
class account
{
protected:
    string name;
    double balance;
    int AccNo;
public:
    void operations()
    {
        int r = 0;
        do{
            cout << "1.DEPOSIT" << endl;
            cout << "2.WITHDRAW" << endl;
            cout << "3.CHECK BALANCE" << endl;
            cout << "0.EXIT" << endl;
            cin >> r;
            switch(r)
            {
            case 1:this->depositmoney();
                break;
            case 2:this->withdraw();
                break;
            case 3:this->displaybalance();
                break;
            case 0:cout << "Exiting" << endl;
                break;
            default:
                break;
            }
        }
        while(r != 0);
    }
    account(string Name, double bal)
    {
        name = Name;
        balance = bal;
        AccNo = temp++;
    }
    void displaybalance()
    {
        cout << "name :" << name << endl;
        cout << "A/C" << AccNo << endl;
        cout << "your balance is " << balance << endl;
    }
    void depositmoney()
    {
        float deposit;
        cout << "enter deposit" << endl;
        cin >> deposit;
        balance += deposit;
    }
protected:
    void withdraw()
    {
        float withdrawal;
        cout << "enter witdrawal amount" << endl;
        cin >> withdrawal;
        if(balance >= withdrawal)
        {
            balance -= withdrawal;
        }
        else
        {
            cout << "insufficient funds" << endl;
        }
    }
};
class Sav_account :public account
{
private:
    double const CI = 5;
    void depositinterest()
    {
        balance += balance*CI / 100;
    }
public:
    Sav_account(string Name, double bal) :account(Name, bal)
    {
        AccType = 0;
    }
    void depositmoney()
    {
        account::depositmoney();
        depositinterest();
    }
};
void main()
{
    Sav_account *account1 = new Sav_account("Shaw", 50000);
    account1->operations();// DEPOSIT RESULTS IN NO INTEREST
    account1->displaybalance();
    account1->depositmoney(); // **DEPOSIT FUNCTION OF Sav_account CALLS                      interest function**
    account1->displaybalance();
    _getch();
}