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

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;
}

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