PLease go thru the below function and give me the reason why the first read works and the next two dont!!!!

public void getData()
{

            Student stud=new Student();
            System.Console.WriteLine("\n Enter the number of students(<11) ");
            num=(int)System.Console.Read();// Statement gets executed
            System.Console.WriteLine("Enter the Rollnumber,Name and Percentages");
            stud.Rollnumber=(int)System.Console.Read();//statement never got executed in the console
            stud.Name=System.Console.ReadLine();// statement never got executed in the console
            stud.percentage=(float)System.Console.Read();
            if(stud.percentage>80)
                stud.Grade=grade.A;
            else if(stud.percentage<40)
                stud.Grade=grade.F;
            if(stud.percentage>50 && stud.percentage<60)
                stud.Grade=grade.D;
            if(stud.percentage>70 && stud.percentage<80)
                stud.Grade=grade.B;
            if(stud.percentage>60 && stud.percentage<70)
                stud.Grade=grade.C;
            students[i].Name=stud.Name;
            students[i].Rollnumber=stud.Rollnumber;
            students[i].percentage=stud.percentage;
            students[i].Grade=stud.Grade;

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