C++否则表达式错误

我检查了我的嵌套if语句和右括号...不知道为什么，但我在编译时收到"预期表达式"错误。错误发生在以下代码中：else if (secondCourseEnrollCount >= 20)

这是我的代码：

#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;
int main()
{
    string myName, firstCourseID, secondCourseID, thirdCourseID;
    int studentID, firstCourseEnrollCount, secondCourseEnrollCount, thirdCourseEnrollCount;

    firstCourseEnrollCount=secondCourseEnrollCount=20;
    thirdCourseEnrollCount=17;
    cout << "Please Type Your Name: ";
    cin >> myName;
    cout << "Please Type Your Student ID Number without spaces: ";
    cin >> studentID;
    cout << "Please Type Your First Requested Course ID: ";
    cin >> firstCourseID;
    cout << "Please Type Your Second Requested Course ID: ";
    cin >> secondCourseID;
    cout << "Please Type Your Third Requested Course ID: ";
    cin >> thirdCourseID;
    // First If Statement Should Come Here
    if (firstCourseEnrollCount >= 20)
    {
        // True Path Here
        cout << "The first choice currently has 20 Students, " << myName << endl;
        cout << firstCourseID << " is Already at Maximum Enrollment, so you have not been added to the class";

        // False Path Here
        // Second If Statement Here
            else if (secondCourseEnrollCount >= 20)
            {
                // True Path Here
                cout << "The second choice currently has 20 Students, " << myName << endl;
                cout << secondCourseID << " is Already at Maximum Enrollment, so you have not been added to the class";
                // False Path Here
                // 3rd If Statement Here
                    else if (thirdCourseEnrollCount >= 20)
                    {
                        // True Path Here
                        cout << "The third choice currently has 20 Students, " << myName << endl;
                        cout << thirdCourseID << " is Already at Maximum Enrollment, so you have not been added to the class";
                        //False Path Here
                        else
                        {
                            cout << "All Three Courses Have Seats Remaining, " << myName << endl;
                            cout << "You have been enrolled in " << firstCourseID << endl;
                            cout << "You have been enrolled in " << secondCourseID << endl;
                            cout << "You have been enrolled in " << thirdCourseID << endl;
                        }
                    }// End 3rd If Statement
            }// End 2nd If Statement
    }// End 1st If Statement

    return 0;
}