i have written a class and some code. my next thing to do is put in validation. here is what i have to do:

Modify your StudentGrade class such that the "set" methods perform data validation. A student ID should be in the range of 10000-50000, and a grade should be in the range 0 - 100. Use a single "if" statement (using the && operator) in each "set" method.

Here is my code:

#include <iostream>
    using std::cout;
    using std::cin;
    using std::endl;

    #include <string>
    using std::string;
    using std::getline;

    class StudentGrade
  {
    public:
    //function that sets the student ID
    void setStudentID( string number )
    {
        studentID = number; //store the course name in the object
    }

    //function that gets the student ID
    string getStudentID()
    {
        return studentID; //returns the objects Student ID
    }

    void setTestScore( string score )
    {
        testScore = score;
    }

    string getTestScore()
    {
        return testScore;
    }

    void displayMessage()
    {
        cout << "Student " << getStudentID() << " has a score of " << getTestScore() << endl;
    }
    private:
    string studentID;
    string testScore;
};

    int main()
   {
    string studentIDnumber;
    string studentTestscore;
    StudentGrade myStudentID;


    cout << "Student ID is: " <<myStudentID.getStudentID() << endl;

    cout << "\nPlease enter the Student ID number:" << endl;
    getline( cin, studentIDnumber );
    myStudentID.setStudentID( studentIDnumber );

    cout << endl;

    cout << "Student test score is: " <<myStudentID.getTestScore() << endl;

    cout << "\nPlease enter the Student Test Score:" << endl;
    getline( cin, studentTestscore );
    myStudentID.setTestScore( studentTestscore );

    cout << endl;

    myStudentID.displayMessage();
    return 0;
   }
every time i try and put in the data validation and the if statement it crashes the program. what am i doing wrong? how do i put in the data validation?