Project not building

[dday9]

I'm a vb.net guy and I'm trying to learn C++. I understand the OO concept very well, and I consider myself a decent programmer. Currently what I'm using is Microsoft Visual C++ 2010 Express and I'm trying to create a console application that will convert Fahrenheit to Celsius:

#include <iostream>

using namespace std;

int main()
{
	cout << "This is a Fahrenheit to Celcius conversion tool. The temperature can be in two different formats: 74 -or- 74.0.";

	//Loop until the user doesn't want to continue
	bool looping = true;
	do
	{
		looping = conversion;
	} while (looping = true);

	return 0;
}

bool conversion()
{
	//fahrenheit and celsius variables
	double fahrenheit;
	double celsius;
	cout << "Please type in the Fahrenheit degree:";

	//fahrenheit will be what the user entered
	cin >> fahrenheit;

	//celsius converted here
	celsius = f_to_c(fahrenheit);

	//print out the celsius degree
	cout << fahrenheit << "degrees = " << celsius << "degrees";

	cout << "Continue? y - yes or n - no";

	//return true/false based on if the user wants to keep converting
	if (cin >> "y")
	{
		return true;
	}
	else
	{
		return false;
	}
}

double f_to_c(double f)
{
	//celsius = fahrenheit - 32 * 5 / 9, ignoring PEMDAS
	double c = (f - 32) * 5 / 9;

	//return the celsius value
	return c;
}

However, when building this I get an error:
-edit- it's to big to put in this post, so I'll put it in the next post.

It seems as though I'm doing everything correctly, but I don't know, I'm no C++ expert :P

[MrHutch]

You need brackets after the word "conversion" on line 13.

You also need to either put the functions before main or forward declare them. I would do the latter.

[metulburr]

You need to initialize your functions before main() or define the functions before main.

= is assignment, == is equals
} while (looping = true);

[dday9]

I believe I forward declared properly:

#include <iostream>

using namespace std;

//Forward declare our two functions
bool conversion();
double f_to_c(double f);

//Main!
int main()
{
	cout << "This is a Fahrenheit to Celcius conversion tool. The temperature can be in two different formats: 74 -or- 74.0.";

	//Loop until the user doesn't want to continue
	bool looping = true;
	do
	{
		looping = conversion;
		{};
	} while (looping == true);

	return 0;
}

bool conversion()
{
	//fahrenheit and celsius variables
	double fahrenheit;
	double celsius;
	cout << "Please type in the Fahrenheit degree:";

	//fahrenheit will be what the user entered
	cin >> fahrenheit;

	//celsius converted here
	celsius = f_to_c(fahrenheit);

	//print out the celsius degree
	cout << fahrenheit << "degrees = " << celsius << "degrees";

	cout << "Continue? y - yes or n - no";

	//return true/false based on if the user wants to keep converting
	if (cin >> "y")
	{
		return true;
	}
	else
	{
		return false;
	}
}

double f_to_c(double f)
{
	//celsius = fahrenheit - 32 * 5 / 9, ignoring PEMDAS
	double c = (f - 32) * 5 / 9;

	//return the celsius value
	return c;
}

I've also added two brackets after conversion as suggested in post #2. Unfortunately it still won't build. This is the error I get:
-Edit- Still to large, I will try to post it on the next post... again.

[Manga]

you can call functions from main. do not define them in main.

[MrHutch]

The line should be:

looping = conversion();

You could actually shorten the whole thing to...

while( conversion() ){;}

I feel the general layout is a bit off, though.

[dday9]

I didn't think that I was defining them in main, I thought that declaring the two functions above the Main() was forward declaring. Although I did just google forward declare c++ and that's how it told me to do it.

[metulburr]

this is not calling the function, you need paren
looping = conversion;

I am assuming here instead of:
if (cin >> "y")

you mean:

	char choice;
	cin >> choice;

	//return true/false based on if the user wants to keep converting
	if (choice ==  'y')

I am not sure why added this:
{};

[Manga]

to call a function is like this...

conversion();
if looping = what conversion returns, true or false then...

looping = conversion();

[Manga]

hold on a moment... I am using same compiler as you so let me copy and paste then I will get back with you.

[dday9]

Now that I made the changes y'all suggested I come up with this:

#include <iostream>

using namespace std;

//Forward declare our two functions
bool conversion();
double f_to_c(double f);

//Main!
int main()
{
	cout << "This is a Fahrenheit to Celcius conversion tool. The temperature can be in two different formats: 74 -or- 74.0.";

	//Loop until the user doesn't want to continue
	while( conversion() ){;}


	return 0;
}

bool conversion()
{
	//fahrenheit and celsius variables
	double fahrenheit;
	double celsius;
	cout << "Please type in the Fahrenheit degree:";

	//fahrenheit will be what the user entered
	cin >> fahrenheit;

	//celsius converted here
	celsius = f_to_c(fahrenheit);

	//print out the celsius degree
	cout << fahrenheit << "degrees = " << celsius << "degrees";

		char choice;
	cin >> choice;

	//return true/false based on if the user wants to keep converting
	if (choice ==  'y')
	{
		return true;
	}
	else
	{
		return false;
	}
}

double f_to_c(double f)
{
	//celsius = fahrenheit - 32 * 5 / 9, ignoring PEMDAS
	double c = (f - 32) * 5 / 9;

	//return the celsius value
	return c;
}

And it works. My next question is, in the conditional statement where I check if it's y or not, why do I use single quotation marks instead of double? I would assume that with y being a string, it'd be double quotes.

[Manga]

you beat me good job dude. I was just about to paste in the fix!!

anyways..
choice == 'y'
because "y" is a character const.

[dday9]

Oh ok, that makes sense. I'm trying to learn C++ by diving into projects, just like I did with vb.net. Starting from small ones like this to full blown data management systems, so it's all a learning process. More than likely I'll start up a new thread :]

[Manga]

but you forgot line 54...

can you spot the error? think int math vs double

although your format might still work... lucky just watch that in future.