"expected primary expression __"是什么意思？

我正在尝试编写一个程序来计算某个酒店租房的成本。该计划要求租金费用，要预订多少天的房间以及营业税。我应该实施如果语句按顺序计算基于房间的租金时间以及如何租用房间的折扣。当我尝试设置将使用哪种折扣的参数时，我会遇到一个错误，说"预期eartial表达式__"在我在第45-51行中使用的每个表达式变化。

#include <iostream>
using namespace std;
int main()
{
    int Reason;
    double Rent, totRent;
    double SalesTax, calcST;
    double TimeDiscount, totDiscount;
    int numRooms;
    int RentTime;
    int tenRooms, twentyRooms, thirtyRooms;
    int tenTotal, twentyTotal, thirtyTotal, RegularPricing;
    cout << "How much is the cost of renting a room: " << endl;
    cin >> Rent;
    cout << "Are you staying for a special reason i.e. wedding/conference: " << endl;
    cin >> Reason;
    cout << "How many days are the rooms going to be booked " << endl;
    cin >> RentTime;
    cout << "What is the sales tax: " << endl;
    cin >> SalesTax;
    SalesTax = Rent * SalesTax;
    calcST = Rent + SalesTax;
    totRent = (Rent * numRooms) + RentTime;
    if (Reason = 1)
    {
        cout << "How many are rooms going to be booked: " << endl;
        cin >> numRooms;
    }
    if (RentTime >= 3)
    {
        TimeDiscount = .05 * Rent;
        totDiscount = Rent + TimeDiscount;
    }
    if (numRooms >= 10)
    {
        tenRooms = Rent * .10;
        tenTotal = (totRent + calcST) - (tenRooms + totDiscount);
        cout << "Your total fee is: $" << tenTotal << endl;
    }
    if (numRooms >= 11 && <= 20) //45
    {
        twentyRooms = Rent * .20 * SalesTax * TimeDiscount;
        twentyTotal = (totRent + calcST) - (twentyRooms + totDiscount);
        cout << "Your total fee is: $" << twentyTotal << endl;
    }
    if (numRooms >= 21 && >= 30 && >> 30) //51
    {
        thirtyRooms = Rent * .30 + SalesTax + TimeDiscount;
        thirtyTotal = (totRent + calcST) - (thirtyRooms + totDiscount);
        cout << "Your total fee is: $" << thirtyRooms << endl;
    }
    else
    {
        RegularPricing = Rent * RentTime + SalesTax;
        cout << "Your Total Fee is: $" << RegularPricing << endl;
    }
    cout << "The cost of renting one room is: $" << Rent << endl;
    cout << "Number of rooms booked : " << numRooms << endl;
    cout << "Days booked: " << RentTime << endl;
    cout << "The sales tax is: $" << calcST << endl;

    return 0;
}