Boolean in Function (Menu Program)

[Dkmariolink]

My professor seriously threw too much at us over spring break... Anyway, I have to create a boolean function that checks rather or not the values entered by the users range from 0-100, but I have no idea at all how to do this, with my program already being super complicated as it is... Anyway, here is the code, and the boolean function is at the bottom, I only declared the prototype, because I have no clue as to what my next step would be. Any help would be appreciated.

int menu();
void DisplayGrades (float, float, float, float, float, float); // In this function, it will display the grades the user enters. Used for choice 2.
float AssignmentGrade(float, float, float, float, float);
float LabTestGrade(float, float, float, float);                         // Prototypes to help me remember functions.
float LectureTestGrade(float, float, float, float, float);
float PostLabGrade(float, float, float, float, float, float, float, float, float, float);
float QuizGrade (float, float, float, float, float, float, float, float, float, float);
float ClickerGrade (float, float);
bool Gradeisvalid (float);
bool Choiceisvalid (int);





int main()
{
    float asgnment = 0, asgnment1 = 0, asgnment2 = 0, asgnment3 = 0,
        asgnment4 = 0, labtest = 0, labtest1 = 0, labtest2 = 0,
        labtest3 = 0, lecturetest = 0, lecturetest1 = 0, lecturetest2 = 0,   // Variables declared
        lecturetest3 = 0, lecturetest4 = 0, postlab = 0, p1 = 0, p2 = 0, p3 = 0, p4 = 0,
        p5 = 0, p6 = 0, p7 = 0, p8 = 0, p9 = 0, quiz = 0, quiz1 = 0, quiz2 = 0, quiz3 = 0, quiz4 = 0, quiz5 = 0,
        quiz6 = 0, quiz7 = 0, quiz8 = 0, quiz9 = 0, clicker = 0, clickergrade = 0, grade = 0;
    int choice;
    while(1)
    {
        choice = menu();
        if (choice ==4) break;
        switch (choice)

                    {
                                case 1:
                               asgnment=AssignmentGrade(asgnment, asgnment1, asgnment2, asgnment3, asgnment4);
                               labtest = LabTestGrade(labtest, labtest1, labtest2, labtest3);
                               lecturetest = LectureTestGrade(lecturetest, lecturetest1,  lecturetest2, lecturetest3, lecturetest4); // Typed this out to help remind of what I used
                               postlab = PostLabGrade(postlab, p1, p2, p3, p4, p5, p6, p7, p8, p9);
                               quiz = QuizGrade(quiz, quiz1, quiz2, quiz3, quiz4, quiz5, quiz6, quiz7, quiz8, quiz9);
                               clickergrade = ClickerGrade (clickergrade, clicker);
                                break;
                                case 2:
                                DisplayGrades (asgnment, labtest, lecturetest, postlab, quiz, clickergrade);
                                break;
                                case 3:
                                grade =  asgnment + labtest + lecturetest + postlab + quiz + clickergrade;
                                cout << "Your total grade is " << grade << "%" << endl;
                                if (grade <= 100 && grade >=90)
                                   cout << "Letter grade A" << endl << endl;
                                else if (grade <= 89 &&grade >= 80)
                                    cout << "Letter grade B" << endl << endl;
                                else if (grade <= 79 && grade >=70)
                                    cout << "Letter grade C" << endl << endl;
                                else if (grade <= 69 && grade >=60)
                                    cout << "Letter grade D, a little more!" << endl << endl;
                                else if (grade <= 59 && grade >=1)
                                    cout << "Grade of F, you can do better!" << endl << endl;
                                else if (grade ==0)
                                    cout << "Don't press 3 first!" << endl << endl;
    }

    }




return 0;
}

//Menu Options

int menu()
{
    int choice;
    cout << "Please select an option below." << endl << endl;
    cout << "1. Enter Grades" << endl;
    cout << "2. Display Grades" << endl;
    cout << "3. Show Overall Grade" << endl;
    cout << "4. Exit the Program"<< endl;
    cout << "Enter your choice... ";
    cin >> choice;
    return choice;
}

//AssignmentGrade Function

float AssignmentGrade(float asgnment, float asgnment1, float asgnment2, float asgnment3, float asgnment4)
{
    cout << "Okay, lets get started!" << endl;
    cout << "Please enter your first assignment grade " << endl;
    cin >> asgnment1;
    cout << endl << "Enter your second assignment grade " << endl;
    cin >> asgnment2;
    cout << endl << "Enter your final assignment grade " << endl;
    cin >> asgnment3;
    asgnment = asgnment1*0.05 + asgnment2*0.05 + asgnment3 *0.05;
    return asgnment;
}
// LabTestGrade Function

float LabTestGrade(float labtest, float labtest1, float labtest2, float labtest3)
{
  cout << "Now you are going to enter your 3 lab test grades. " <<endl;
  cout << "Please enter your first lab test score" <<endl;
  cin >> labtest1;
  cout << endl << "Now enter your second score" <<endl;
  cin >> labtest2;
  cout << endl << "Lastly, your final score" <<endl;
  cin >> labtest3;
  labtest = labtest1*0.10 + labtest2*0.10 + labtest3*0.10;
  return labtest;

}
// LectureTestGrade Function
float LectureTestGrade (float lecturetest, float lecturetest1, float lecturetest2, float lecturetest3, float lecturetest4)
{
  cout << "Next, you're going to enter your 4 Lecture Test grades." << endl;
  cout << "Please enter your first lecture test grade" << endl;
  cin >> lecturetest1;
  cout << endl << "Now enter your second grade" << endl;
  cin >> lecturetest2;
  cout << endl << "Next, your third score" << endl;
  cin >> lecturetest3;
  cout << endl << "Finally, your fourth score" << endl;
  cin >> lecturetest4;
  lecturetest = lecturetest1*0.10 + lecturetest2*0.10 + lecturetest3*0.10 + lecturetest4*0.10;
  return lecturetest;
}
// PostLabGrade Function
float PostLabGrade(float postlab, float p1, float p2, float p3, float p4, float p5, float p6, float p7, float p8, float p9)
{
  cout << "Now, enter your 9 Post Lab grades" << endl;
  cin >> p1 >> p2 >> p3 >> p4 >> p5 >> p6 >> p7 >> p8 >> p9;
  postlab = p1*0.003 + p2*0.003 + p3*0.003 + p4*0.003 + p5*0.003 + p6*0.003 + p7*0.003 + p8*0.003 + p9*0.003;
  return postlab;

}
// QuizGrade Function
float QuizGrade (float quiz, float quiz1, float quiz2, float quiz3, float quiz4, float quiz5, float quiz6, float quiz7, float quiz8, float quiz9)
{
  cout << "9 more grades to enter, this time, please enter your quiz grades" << endl;
  cin >> quiz1 >> quiz2 >> quiz3 >> quiz4 >> quiz5 >> quiz6 >> quiz7 >> quiz8 >> quiz9;
  quiz = quiz1*0.004 + quiz2*0.004 + quiz3*0.004 + quiz4*0.004 + quiz5*0.004 + quiz6*0.004 + quiz7*0.004 + quiz8*0.004 + quiz9*0.004;
  return quiz;
}
// ClickerGrade Function
float ClickerGrade (float clickergrade, float clicker)
{
  cout << "Almost done! Now, enter your total clicker grade." << endl;
  cin >> clicker;
  cout << "Finished! Next..." << endl;
  clickergrade = clicker*0.037;
  return clickergrade;
}
// DisplayGrade Function
void DisplayGrades (float asgnment, float labtest, float lecturetest, float postlab, float quiz, float clickergrade)
{
cout << "Grades" << endl << endl;
cout  << "Assignment";
cout << std::right << std::setw(7)<< asgnment << "%" << endl;
cout  << "Lab Test";
cout << std::right << std::setw(9)<< labtest << "%" << endl;
cout << "Lecture";
cout << std::right << std::setw(10)<< lecturetest << "%" << endl;
cout << "Post Lab";
cout << std::right << std::setw(9)<< postlab << "%" << endl;
cout << "Quiz";
cout << std::right << std::setw(13)<< quiz << "%" << endl;
cout <<"Clicker";
cout << std::right << std::setw(10)<< clickergrade << "%" << endl;
}
// Valid grade function
bool Gradeisvalid (float score)
{


}

[Bdanielz]

#include <iostream>

bool Gradeisvalid (float score);

using namespace std;

int main() {

    cout << std::boolalpha << Gradeisvalid (200) << endl;
    cout << std::boolalpha << Gradeisvalid (-10) << endl;
    cout << std::boolalpha << Gradeisvalid (50) << endl;

    return 0;
}

// Valid grade function
bool Gradeisvalid (float score)
{
    // lets assume bad input.
    // Beacuse humans.
    bool returnVALUE = false;

    if(0 <= score && score <= 100){

        returnVALUE = true;
    }
    return  returnVALUE;
}

false
false
true

[Thomas1965]

@Bdanielz,

it can be much shorter:

bool GradeIsValid (float score)
{
  return (score >= 0 && score <= 100);
}

[mikepann83]

@Thomas1965

I tried your code and it works! Thanks a ton.

it can be much shorter:

bool GradeIsValid (float score)
{
return (score >= 0 && score <= 100);
}


Thanks
Mike
http://www.fita.in/python-training-in-chennai/