calling a function??

Hi all,
I'm a rookie when it comes to C but I'm learning. I was wondering if someone can give me advice on my code? I'm trying to write a function that receives from the calling program the length and width of a room in decimal feet. The function should then caculate and return the number of square yards in the room.

I would like my main program to prompt for the dimensions of the room in decimal feet and the cost of a yard of carpet. Then, I would like to display both the number of yards needed and the total cost of the carpet.

I think I have my code in my function mixed up with the code in my main program. I didn't totally finish because I'm at this roadblock. Please, this is probably basic to some, but I'm just starting out. Thanks in advance for any advice. Here is my code:

Code:

#include <iostream.h>
#include <stdlib.h>

double room(double length, width, yds)
{
yds=9/(length*width);
}

return yds;

int main()
{
double length, width, cost, total;

cout<<"Enter the width of the room:";
cin>>width;
cout<<"Enter the length of the room:";
cin>>length;
cout<<"Enter the cost of a yard of carpet:";
cin>>cost;

total=room*cost;

Code:

double room(double length, double width, double yds)
{
return yds=9/(length*width);
}

Code:

total = room(length, width, yds) * cost;

I think you need to read up on how to use functions and how to properly syntax them.

I have given you a code for a simple function which calculates the square of a given number.

You should be able to read through and adapt it to meet the needs of your specific program.

Code:

#include <iostream>

//function declaration
//always before int main()
//semi colon needed.
//If more than one variable is used
//separate them with a comma
int square(float);

using namespace std;

int main()
{
    float number;
    cout<<"Enter a number:";
    cin>>number;
    
    // call the function 'square' passing in the variable 'number'
    // into it. Here you don't need to define its type
    //semicolon needed
    square(number);
    
    cout<<"Press any key to exit"<<endl;
    char pause;
    cin>>pause;
    
}


//function definition
//here you have to declare what type the variable is
//Here the semi colon is ommitted.
int square(float number)
{
    
    cout<<"The number squared was"<<number*number<<endl;
    
}