need help with program in xcode

[jrgaskey]

the following program is supposed to take an input to choose to convert from F to C or C to F. The problem i am having right now is that it is telling me that no function exists for FtoC or CtoF and as you can see below, the function clearly exists. I use Visual Studio in class but have to use xcode at home as I have a Mac and there seems to be a few differences when programming ( I think, i am probably a moron but this is killing me). I need help fixing this and my prof is out to lunch. any help would be greatly appreciated.

#include <iostream>
#include <ostream>
#include <iomanip>
#include <cmath>
using namespace std;

//void getdisplayMenu( );
//void getMenuSelection (char a);
//void getStartEndAndIncrement(float& st, float& ending, float& i);
//void getCtoF(float Fahr);
//void getFtoC(float Celsius);
void displayMenu( )
{
cout<< "Would you like to convert from 'C'elsius to Fahrenheit; 'F'ahrenheit to Celsius; or 'Q'uit: ";
}
void MenuSelection (char a)
{
char b;
cin >> b;
a=b;
}
void getStartEndAndIncrement(float& st, float& ending, float& i)
{
cout<< "Input the starting temp:";
cin >> st;
cout << "Input the ending temp: ";
cin >> ending;
cout << "Input the increment of calculation: ";
cin >> i;
}
void CtoF(float q)
{
float Fahr;
Fahr= (9.0*q)/5.0+32.0;
}
void FtoC(float q)
{
float Celsius;
Celsius= 5.0*(q-32.0)/9.0;
}
void displayTable( )
{
cout << fixed << setprecision (2);
cout << setw(8) << char (248)<< "C" << setw (8) << char (248) << "F" << endl;
}
int main()
{
char a;
float st, ending, i, Celsius, Fahr;
displayMenu();
getStartEndAndIncrement(st, ending, i);
MenuSelection(a);
for(float q=st;q<ending;q=q+i)
{
switch(a)
{
case 'C':
CtoF(Fahr);
break;
case 'F':
FtoC (Celsius);
break;
case 'Q':
break;
}
cout << setw(4) << Celsius << setw (6) << Fahr << endl;
}
return 0;
}

[MaxLascombe]

Do these things and it should work:
1.In your CtoF() function, add 'return Fahr;' at the end of the function.
2.In your FtoC() function, add 'return Celcius;' at the end of the function.
3.In your main() function, add 'float Fahr = ' at the beginning of the line where you wrote 'CtoF(Fahr)'.
4.In your main() function, add 'float Celcius = ' at the beginning of the line where you wrote 'FtoC(Celcius)'.

That should work.

[jrgaskey]

1. it gives an error "cannot return value for void function"
2. same as 1
3. it gives the error "cannot initialize a variable of type 'float' with an rvalue of type void
4. same

Thanks for the help but I have to turn this in. I did finally get it to compile, problem is it is giving all 0's for temps can't figure that one out either.

new program :

#include <iostream>
#include <ostream>
#include <iomanip>
#include <cmath>
using namespace std;

void displayMenu()
{
cout << "Would you like to convert from 'C'elsius to Fahrenheit; 'F'ahrenheit to Celsius; or 'Q'uit: ";
}
void MenuSelection (char a)
{
cin >> a;
}
void StartEndAndIncrement(float & st, float & ending,float & i)
{
cout<< "Input the starting temp:";
cin >> st;
cout << "Input the ending temp: ";
cin >> ending;
cout << "Input the increment of calculation: ";
cin >> i;
}
void CtoF(float q)
{
float Fahr=0.0;
Fahr = (9.0*q)/5.0+32.0;
}
void FtoC(float& q)
{
float Celsius= 0.0;
Celsius= 5.0*(q-32.0)/9.0;
}
int main()
{
char a = 0;
float st=0.0, ending=0.0, i=0.0, Celsius=0.0, Fahr=0.0;
displayMenu ();
MenuSelection (a);
StartEndAndIncrement (st, ending, i);
cout << setw (5) << char(248) << "C" << setw (8) << char (248) << "F" << endl;
for(float q=st;q<ending;q=q+i)
{
switch(a)
{
case 'C':
CtoF(Fahr);
break;
case 'F':
FtoC(Celsius);
break;
case 'Q':
break;
}

cout << setw(4) << Celsius << setw (6) << Fahr << endl;
}
return 0;
}

[HiteshVaghani1]

Make Celsius and Fahr as Global variable.
and remove declaration of that variable from function CtoF(.....) and FtoC(...)
like this

void FtoC(float& q)
{
    Celsius= 5.0*(q-32.0)/9.0;
}

please use code tags..

[Volatile Pulse]

Do NOT use global variables. Either pass values by reference, create a data type function beside void, or both. Refrain from using any global variables unless absolutely necessary.

[MaxLascombe]

Just change the 'void' from the functions to 'int'. It should work.

[MaxLascombe]

And for my 3. and 4., just change the name of the variables to something else. (eg. 'float Celcius = FtoC(Celcius);' -> 'float Cel = FtoC(Celcius);