Question

DO NOT USE ARRAYS IF YOU KNOW ABOUT ARRAYS, I WANT YOU TO USE 3 VARIABLES, IT WILL FORCE YOU TO USE COMPOUND LOGICAL STATEMENTS FOR THE IF STATEMENTS.

Create a program that will display a menu to the user. The choices should be as follows:

1. Enter 3 grades
2. Show average (with the 3 grades) and letter grade
3. Show highest grade
4. Show lowest grade
5. Exit

If you want to put the menu into a function you may. The program should use a switch statement for using the appropriate function based on the user's choice. Each option should be implemented in its own function (I use the word function 1, function 2, I want you to come up with appropriate names for the functions). Initialize the variables for grades randomly between 50-100 so if the user select show average as their first choice, there will be some random grades in the variables already.

You should have the following functions:

Function 1: This function will ask the user for a single grade that will be passed back to the main function. The function should validate that the grade is in the range between 0-100 otherwise ask the user to enter another grade. This function should be called 3 times from the main to place the appropriate values into the grade variables.

Function 2: This function will calculate the average of the 3 grades passed in and display the average with 1 decimal place and display the letter grade based on the following scale:

Average	Letter Grade
90 - 100	A
80 - 90	B
70 - 79	C
60 - 69	D
Below 60	F

Function 3: This function will receive 3 grades as parameters and returns the highest grade to the main. The main will use that value to display the highest grade. Do not display the highest grade in this function.

Function 4: This function will receive 3 grades as parameters and returns the lowest grade to the main. The main will use that value to display the lowest grade. Do not display the highest grade in this function.

Use a loop to repeat the entire program until the users hits 5 to exit.

Answer 1

#include<iostream>
#include<iomanip>
using namespace std;
float fun1()
{
   float f;
  
   do//validating input
   {cout<<"Enter a grade(1-100):";
   cin>>f;
   if(f<1 ||100<f)cout<<"Invalid grade Enter again\n";
   }while(f<1 ||100<f);//if not in th range
  
return f;  
}
void fun2(float a,float b,float cc)
{
   //finding average
   float av = (a+b+cc)/3;
   cout<<"Average :"<<setprecision(3)<<av<<endl;//displaying upto 1 decimal place
   char c;
   if(90<=av)
   c='A';
   else if(80<=av)
   c='B';
   else if(70<=av)
   c='C';
   else if(60<=av)
   c='D';
   else
   c='F';
   cout<<"Letter grade: "<<c<<endl;
}  

float fun3(float a,float b,float c)
{
   int h=a;
   if(h<b)h=b;
   if(h<c)h=c;
   return h;//returning highest grade
  
}
float fun4(float a,float b,float c)
{
   int h=a;
   if(h>b)h=b;
   if(h>c)h=c;
   return h;//returning smallest grade
  
}
int main()
{
   int cc=0;
   float a=1,b=1,c=1;
   while(1)
   {
       cout<<"Menu :\n";
       cout<<"1:Enter 3 grades\n2:Show average (with the 3 grades) and letter grade\n3:Show highest grade\n4:Show lowest grade\n5:Exit\nEnter:";
       cin>>cc;
       switch(cc)
       {
           case 1://callling function1 3 times
               a=fun1();
               b=fun1();
               c=fun1();
               break;
           case 2:
               fun2(a,b,c);
               break;
           case 3:
               cout<<"Highest grade is :"<<fun3(a,b,c)<<endl;
               break;
           case 4:
               cout<<"Smallest grade is :"<<fun4(a,b,c)<<endl;
               break;
           case 5:
               break;  
       }
       if(cc==5)break;  
   }
  
   return 0;
}

output:

Menu :
1:Enter 3 grades
2:Show average (with the 3 grades) and letter grade
3:Show highest grade
4:Show lowest grade
5:Exit
Enter:1
Enter a grade(1-100):20
Enter a grade(1-100):40
Enter a grade(1-100):7
Menu :
1:Enter 3 grades
2:Show average (with the 3 grades) and letter grade
3:Show highest grade
4:Show lowest grade
5:Exit
Enter:2
Average :22.3
Letter grade: F
Menu :
1:Enter 3 grades
2:Show average (with the 3 grades) and letter grade
3:Show highest grade
4:Show lowest grade
5:Exit
Enter:3
Highest grade is :40
Menu :
1:Enter 3 grades
2:Show average (with the 3 grades) and letter grade
3:Show highest grade
4:Show lowest grade
5:Exit
Enter:4
Smallest grade is :7
Menu :
1:Enter 3 grades
2:Show average (with the 3 grades) and letter grade
3:Show highest grade
4:Show lowest grade
5:Exit
Enter:5

Process exited normally.
Press any key to continue . . .