   Some part i havent learnd, so I cant solve it
  Exercise :Given the diagram below.  Transform the diagram into C++ program. Class GradePrivate members :char letter;float score;Public Members :void SetScore( float );float GetScore( );char CalculateGrade ( );Class TestPrivate members :int NumberOfQuestion;float PointsEach;int NumMiss;Public Members :Test( int, int );Grade is given using the table below :> 89  A> 75  B> 60  C< 50  F Sample Program Output :How many questions are on the test? 20 [Enter]How many questions did the student miss? 3 [Enter]The score is 85The grade is B----------------------------------------------------------------------------------------------------------------------------------------------------------------class grade{private:char letter;float score;public:void setscoce (float);float getscore ();char calculategrade();};save as 11.h#include<iostream.h>#include"c:\borlandc\bin\11.h"void grade::setscore(float n){score = n;}float grade::getscore();{return score;}char grade::calculategrade(){if (score>89) letter="A";else if (score>75) letter = "B";else if (score>60) letter = "C";else if (score>50) letter = "F";return grade;};save as 11.cpp#include"c:\borlandc\bin\11.cpp"class test:public grade{private:int numberofquestion;float pointseach;int nummiss;public:test(int, int);};================================================================================This is what I done so far, and the 3rd last time I cant solve it coz teacher havent tought us about it :S   
  I'll help with some of the smaller errors, but we don't generally answer homework questions here. And, I doubt that the teacher would give you homework on something that you haven't been taught.Where you have letter="A"; and all of those, because the variable 'letter' is a char, you need to use single quotes for the character you're assigning. Using quotation marks in C++ means a string, and you want a single letter.I do reccommend that you see the teacher about the homework for more help.   ;  I'm going to bump this a bit: What part didn't the teacher explain? All I can see is a program that's badly written with a lot of errors, without what you don't understand.People will not fix your homework problems, they will help you explore how to fix it. If you say: I don't understand how to read from the standard input, people will help you on how to do read from the input, but will not write the code for it.Be more specific, and you'll get help.Toolmaker   