The villiage idiot is back! -Function Help Please???

Hello All!

I am in week three of my C++ class and it still isn't coming easy!
I'm quite sure it never will!! This week I am writing a function to compute grades from numeric to alpha. I am getting an error and I have read everything I can get my hands on and still have no idea. I'm sure just one look from any of you will figure out what I have struggled with for days. (yes days - sick and wrong isn't it!)

Below is the code - function and main .cpp and the header .h files.

Thank you in advance for any assistance you can give me.


mz


This is the main.

Code:

---

#include <iostream.h>
#include "Calcgrades.h" 

void main()                                //main program
        {
        float A, B, C, D, F;
          char ngrade, lgrade;
        float count = 0.0;
        A = 0.0;
    B = 0.0;
    C = 0.0;
    D = 0.0;
    F = 0.0;


        while (count < 10.0);  // put at 10 for testing
        {
        Calcgrades();

}
        cout <<"Grades (A, B, C, D, F) :  ";
        cout <<A<< "," <<B<< "," <<C<< "," <<D<< "," <<F<< endl;

}

       

Code:

       

---

This is the function file:

       

Code:

       

---

        char Calcgrades(char lgrade,char ngrade);


{        if (ngrade >= 90)
        {        lgrade = A;
        }
        else if (ngrade >= 80 and < 90)

        {                lgrade = B;
        }
        else if (ngrade >= 70 and < 80)
        {                lgrade = C;
        }
        else if (ngrade >= 60 and < 70)
        {                lgrade = D;       
        }
        else if (ngrade < 50)
        {                lgrade = F;       
        }
                cout >> "calcgrade lgrade :" >> lgrade >>; endl;  //for test

                        return lgrade;
}

---

This is the header file.

---

char Calcgrades();
float count = 0.0;

---

THANKS!!!!

what exactly is the error?

Code:

---

#include <iostream.h>
#include "Calcgrades.h" 

void main()                                //main program
{
        float A, B, C, D, F;
        char ngrade, lgrade;
        float count = 0.0;
        A = 0.0;
        B = 0.0;
        C = 0.0;
        D = 0.0;
        F = 0.0;

        while (count < 10.0);  // put at 10 for testing
        {
                Calcgrades();
        }
        cout <<"Grades (A, B, C, D, F) :  ";
        cout <<A<< "," <<B<< "," <<C<< "," <<D<< "," <<F<< endl;
}

---

function file:

Code:

---

#include "CalcGrades.h"  // Need to include this

char Calcgrades(char lgrade,char ngrade)  // get rid of semicolon here
{
        if (ngrade >= 90)
        {        lgrade = A;
        }
        else if (ngrade >= 80 and < 90)
        {                lgrade = B;
        }
        else if (ngrade >= 70 and < 80)
        {                lgrade = C;
        }
        else if (ngrade >= 60 and < 70)
        {                lgrade = D;       
        }
        else if (ngrade < 50)
        {                lgrade = F;       
        }
        cout >> "calcgrade lgrade :" >> lgrade >>; endl;  //for test
        return lgrade;
}

---

header file

Code:

---


char Calcgrades();
extern float count;  // make this extern or you will get errors from trying to declare it multiple times

---

also, this program will go forever calculating grades because count isn't being incremented, you might want to do that somewhere

here Calcgrades doesn't have any parameters:

Calcgrades();

and here Calcgrades doesn't have any parameters:

char Calcgrades();

but here it does:

char Calcgrades(char lgrade,char ngrade);

Oops.

Also, the semicolon at the end of the last line above is an error. The last line above is a function definition, not a function declaration. Function definitions don't have a semi-colon there, function declarations do.


You return lgrades to main(), but you ignore the return value. Not going to help back in main() that way.

The while loop is unending as you never change the value of count.

I guess that's enough to start with.

also, in your function, you're trying to access the A-F variables, but they haven't been declared inside of that function or as externs in the header file, you would get an undefined variable error from that

One last thingy to add :) :

use :

Code:

---

#include<iostream>

---

instead of:

Code:

---

#include<iostream.h>

---

The first is compliant to the CPP standart and the second is not...

I guess this (possible) infinite loop wasn't intentional?

Code:

---

while (count < 10.0);  // put at 10 for testing
{
        Calcgrades();
}

---

THANK YOU: jverkoey, borko_b, Magos, elad


I can't tell you how much I appreciate your help! After reading all your comments, I realize what a mess this project was!! AND how frustrated I was when I posted, since I forgot to tell everyone what error I was trying to get past!

I have made all the corrections you all have graciously advised me on. The only error I am still getting (and the one I was most frustrated about is:

error C2447: missing function header (old-style formal list?)

I am getting this error on the function file? And I am still getting it after I have made all the changes suggested? I must be doing something wrong (again - imagine that)!


If anyone can enlighten me on this error, I would greatly appreciate it. I looked it up in the MS library and it really doesn't explain it for "dummies". Maybe I should buy that book!?!?!


THANKS again to everyone helping me.

mz

:confused:

I suspect that you are making a function call that doesn't fit the declaration/definition of the function or your function declaration doesn't agree with your function definition. Please post your current code.

Just look here :)

Code:

---

char Calcgrades(char lgrade,char ngrade);  // <- this shouldn't be here! :) :)

{       
  if (ngrade >= 90)
        {        lgrade = A;
        }
        else if (ngrade >= 80 and < 90)

        {                lgrade = B;
        }
        else if (ngrade >= 70 and < 80)
        {                lgrade = C;
        }
        else if (ngrade >= 60 and < 70)
        {                lgrade = D;       
        }
        else if (ngrade < 50)
        {                lgrade = F;       
        }
                cout >> "calcgrade lgrade :" >> lgrade >>; endl;  //for test

                        return lgrade;
}

---

You probably copied the function declaration from the header like this :

Code:

---

//Some header file :
//copy begin
char Calcgrades(char lgrade,char ngrade);
//end

---

Code:

---

//Some cpp file :
//paste begin
char Calcgrades(char lgrade,char ngrade);
{
  ...
}
//end

---

Hey Experts!

This is the new code after I (think) did all that you told me. The header file error is on the function file. Still the same error. I was hoping that the header file error would go away so I can debug and find the other errors I have in the code! (I'm sure there are others!)

THANK YOU FOR YOUR HELP!! IT is amazing to me that you can just look at the code and fire back the errors like this.

mz

HEADER FILE

Code:

---


char Calcgrades(char lgrade,char ngrade, char A,char B,char C,char D,char F);
extern float count; 
char A,B,C,D,F;

---

MAIN FILE

[/CODE]

#include <iostream.h>
#include "Calcgrades.h"

void main() //main program
{
float A, B, C, D, F;
char ngrade, lgrade;
float count = 0.0;
A = 0.0;
B = 0.0;
C = 0.0;
D = 0.0;
F = 0.0;


while (count < 10.0) // put at 10 for testing
{
char ngrade, lgrade;
Calcgrades(ngrade,A, B, C, D, F,lgrade);
cout << "lgrade after Calcgrades is: " <<lgrade<< endl;
}

cout <<"Grades (A, B, C, D, F) : ";
cout <<A<< "," <<B<< "," <<C<< "," <<D<< "," <<F<< endl;

}

[/CODE]

FUNCTION FILE

[/CODE]

#include "Calcgrades.h"


{
char lgrade, char ngrade, char A,char B,char C,char D,char F


if (ngrade >= 90)
{ lgrade = A;
}
else if (ngrade >= 80 and < 90)
{ lgrade = B;
}
else if (ngrade >= 70 and < 80)
{ lgrade = C;
}
else if (ngrade >= 60 and < 70)
{ lgrade = D;
}
else if (ngrade < 50)
{ lgrade = F;
}
cout >> "calcgrade lgrade :" >> lgrade >>; endl; //for test
count = count + 1.0;
return lgrade;



}


[/CODE]

"and" is not an operator in C++. Try && instead and use it like this:

Code:

---

else if ( (ngrade >= 80) && (ngrade < 90) )
{
  lgrade = B;
}

---

Also:

Code:

---

#include "Calcgrades.h"


{
char lgrade, char ngrade, char A,char B,char C,char D,char F

---

Is that supposed to be a function? Maybe you meant:

Code:

---

char Calcgrades(char lgrade,char ngrade, char A,char B,char C,char D,char F)
{
//...

---

I don't know what they are teaching you in the class you are taking, but it isn't up to the standards.

Code:

---

#include <iostream> //unless you have an old compiler
#include "Calcgrades.h"
using namespace std; //again, if you have an old compiler this wont work
int main() //main is never void
{

---

At least change to int main(), but I'm guessing your compiler won't have the new headers.

Also, it doesn't seem like you are bothering to format your code at all, for example:

Code:

---

while (count < 10.0) // put at 10 for testing
{
char ngrade, lgrade;
Calcgrades(ngrade,A, B, C, D, F,lgrade);
cout << "lgrade after Calcgrades is: " <<lgrade<< endl;
}

---

I would indent the code inside the braces, and in you formatted your if statements oddly, but I suppose that is ok unless you have more than one line of code inside the braces

You probably have other problems, but that should get you started

The following code is uncompiled but I think it will work. Compare to your code and try to figure out where and why they are different. Ask questions to learn why they are diferent if you can't figure it out yourself.

Code:

---

//Calcgrades.h//
char Calcgrades(float ngrade);

--------------------------------------------------------------------------------
//MAIN FILE//

#include <iostream.h>
#include "Calcgrades.h"

int main()
{
  char lgrade;
  float ngrade = 45.1;
  int count = 0;

  while (count < 5)
  {
    lgrade = Calcgrades(ngrade);
    cout << "ngrade of " << ngrade << " is lgrade of " << lgrade << endl;
    count++;
    ngrade = ngrade + 10;
  }
}
 

//Calgrades.cpp//

#include "Calcgrades.h"

char Calcgrades(float ngrade)
{
  char letterGrade;
  if (ngrade >= 90)
      letterGrade = 'A';
  else if (ngrade >= 80 && < 90)
      letterGrade = 'B';
  else if (ngrade >= 70 && < 80)
      letterGrade = 'C';
  else if (ngrade >= 60 && < 70)
      letterGrade = 'D';
  else if (ngrade < 60)
      letterGrade = 'F';

  return letterGrade;
}

---

Quote:

---

Originally posted by JaWiB
"and" is not an operator in C++.

---

Actually, "and" is a valid keyword and can be used instead of "&&". However, I wouldn't recommend it since most programmers are more familiar with "&&" and some compilers do not support it (like MSVC++ 6.0).

Wow, I've never heard that before. Learn something new every day I guess

Quote:

---

Originally posted by JaWiB
Wow, I've never heard that before. Learn something new every day I guess

---

Here, learn some others too ;) :

Code:

---

    +--------------------+---------------------+---------------------+
    |alternate  primary | alternate  primary | alternate  primary |
    +--------------------+---------------------+---------------------+
    |  <%          {    |    and        &&    |  and_eq      &=    |
    +--------------------+---------------------+---------------------+
    |  %>          }    |  bitor        |    |  or_eq      |=    |
    +--------------------+---------------------+---------------------+
    |  <:          [    |    or        ||    |  xor_eq      ^=    |
    +--------------------+---------------------+---------------------+
    |  :>          ]    |    xor        ^    |    not        !    |
    +--------------------+---------------------+---------------------+
    |  %:          #    |  compl        ~    |  not_eq      !=    |
    +--------------------+---------------------+---------------------+
    |  %:%:        ##    |  bitand        &    |                    |
    +--------------------+---------------------+---------------------+

---

oo, Interesting info hammer :) Good too know.

Your...making this too hard on yourself I think......

Are there specific requirements/reasons your doing the things your doing on this assignment?

I don't know but...I just think your doing too much work..

Heres the code I came up with, and this doesn't mean I want you to do this at all...it just means that theres easier ways to do things. You don't need to do that much, you know? Simple problems require the simplest solutions :)

Code:

---

#include <iostream>
#include <stdlib.h>
float Calc_Grades(float grade);
float Calc_Grades(float grade)
{
    if (grade >= 0.0f && grade <= 65.0f)
    {
        std::cout << "The grade of " << grade  << " is an F.";
    }
    else if (grade >= 65.01f && grade <= 71.0f)
    {
        std::cout << "The grade of " << grade << " is a D.";
    }
    else if (grade >= 72.0f && grade <= 85.0f)
    {
        std::cout << "The grade of" << grade << " is a C.";
    }
    else if (grade >= 85.01f && grade <= 93.0f)
    {
        std::cout << "The grade of " << grade << " is a B.";
    }
    else if (grade >= 93.01f && grade <= 200.0f)
    {   
        std::cout << "The grade of " << grade << " is an F";
    }
}

int main()
{
    std::cout << "Input grade percentage please: ";
    float percent;
        std::cin >> percent;
    Calc_Grades(percent);
        std::cout << "\n";
    system("pause");
    return 0;
}

---

For one main() is too big, which is a problem alot of times, and you don't need to loop, don't even have to return a value in functions or use a header file.. Just make it simpler is all I think :) But you'll learn that later.

You could even use args in main() so it would make it easier for the user.... so lets say you could pass into main() '95.5' or something and it would calculate and output, without you having to run the program and type it in..you could simply go into run and type in the prog name and enter in the value..but thats more then you have to worry about.

Does this help a little bit?

Code:

---

#include <iostream>
#include <stdlib.h>
using namespace std;

float Calc_Grades(float grade);
float Calc_Grades(float grade)
{
    if (grade >= 0.0f && grade <= 65.0f)
    {
        cout << "The grade of " << grade  << " is an F.";
    }
    else if (grade >= 65.01f && grade <= 71.0f)
    {
        cout << "The grade of " << grade << " is a D.";
    }
    else if (grade >= 72.0f && grade <= 85.0f)
    {
        cout << "The grade of" << grade << " is a C.";
    }
    else if (grade >= 85.01f && grade <= 93.0f)
    {
        cout << "The grade of " << grade << " is a B.";
    }
    else if (grade >= 93.01f && grade <= 200.0f)
    {   
        cout << "The grade of " << grade << " is an F";
    }
}

int main()
{
    cout << "Input grade percentage please: ";
    float percent;
    cin >> percent;
    Calc_Grades(percent);
    cout << "\n";
    system("pause");
    return 0;
}

---

THe code in red is not needed. The reason for this is becasue its before main() so the compiler already knows it was there. You would need this though if you placed float Calc_grades() below int main.

in blue i've added using namespace std;
As you may have noticed I also got rid all the std::'s.
namespace std; automatically adds those just to save alot of hassle.

But other then that the code was right.
And alot easier then ur old code

>THe code in red is not needed. The reason for this is becasue its before main() so the compiler already knows it was there.

My compiler freaks out if I don't declare a function prototype before I define the function.

>in blue i've added using namespace std;
I can understand std::cout better then cout <<.
The reason I did this was so that I could see exactly what was going on in my code, doing the latter just makes me ignorant to the inner workings of the program, thats the only reason why but yes it's not needed other then that. The output is the same.

Quote:

---

Originally posted by Tronic
>THe code in red is not needed. The reason for this is becasue its before main() so the compiler already knows it was there.

My compiler freaks out if I don't declare a function prototype before I define the function.

---

O mine doesnt.
As long as the function is before int main () I don't need the function prototype with devc++.

other then that is outputs the same result ya