C++ Help

[Cruise Control]

I need help, how in blaspheme do I pass data? Can I get an example

  float c(float fa, float ce);
  float f(float fa, float ce);

 int main()
  {
   float choice; //Stored for intial choice.

   cout << "This will convert fahrenheit to celsius.";
   cout << "What do you want to start with, enter your number than print enter.\n";
   cout << " 1. Fahrenheit\n";
   cout << " 2. Celsius\n";
   cin >> choice;

   if (choice==1)
    f();
   else
    c();
 return 0;
}

float c(float fa, float ce)
{
 float fa; //Fahrenheit variable.
 float ce; //Celsius variable.

 cout << "Input your fahrenheit vaulue and press\nENTER.\n";
 cin >> ce;
 fa=1.8*ce+32;
}

float f(float fa, float ce)
{
 float fa; //Fahrenheit variable.
 float ce; //Celsius variable.
 cout << "Input your celsius vaulue and press\nENTER.\n";
 cin >> fa;
 ce=(fa-32)/1.8;

}

[Flying Mullet]

Do you mean use parameters/arguments in your functions?

[Cruise Control]

I guess *updates code*

[Flying Mullet]

There are two ways of passing arguments to a function, by value or by reference.

To pass by value, you simply name the variables in the function definition:

void functionByValue(int a, float b)
{
   // yada yada yada
}

What this does is make a copy of the variables passed to the function and uses them locally, hence, by value.

The other way to pass variables is by reference, which looks like this:

void functionByValue(int a&, float b&)
{
   // yada yada yada
}

What this does is pass a reference (pointer) to the "calling" variable, rather than copy it's value. This means that if you change the value of a to 2 in the function, the original a will be changed to 2. This is useful when you want to return more than one value from a function.

You can also mix and match by reference and by value:

void functionByValue(int a&, float b)
{
   // yada yada yada
}

In this case a local copy of b will be made and a will point to the "calling" a.

Hope this helps.

<b>EDIT:</b> Also, I don't know what book(s) you are using in class, but I used <a href="http://www.amazon.com/gp/product/0672323087/qid=1143132976/sr=2-1/ref=pd_bbs_b_2_1/104-9506222-3431117?s=books&v=glance&n=283155">Object-Oriented Programming in C++ by Robert Lafore</a> and it makes learning C++ a lot easier. Granted, I have the 2nd edition (was the current one when I was in school) and the current one is the 4th edition. But regardless, it's a great book and I highly reccomend it.

[Endless]

  float c(float fa, float ce);
  float f(float fa, float ce);

 int main()
  {
   float choice; //Stored for intial choice.

   cout << "This will convert fahrenheit to celsius.";
   cout << "What do you want to start with, enter your number than print enter.\n";
   cout << " 1. Fahrenheit\n";
   cout << " 2. Celsius\n";
   cin >> choice;

   if (choice==1)
    f();
   else
    c();
 return 0;
}

float c(float fa, float ce)
{
 float fa; //Fahrenheit variable.
 float ce; //Celsius variable.

 cout << "Input your fahrenheit vaulue and press\nENTER.\n";
 cin >> ce;
 fa=1.8*ce+32;
}

float f(float fa, float ce)
{
 float fa; //Fahrenheit variable.
 float ce; //Celsius variable.
 cout << "Input your celsius vaulue and press\nENTER.\n";
 cin >> fa;
 ce=(fa-32)/1.8;

}

Your code makes baby Jesus cry. And I still don't get why some teachers make students use C++ for C programming. Srsly. There's no object in your code, ever.
Anyway.
Why is f defined twice?
Why is c defined twice?
Why did you define f and c to use two parameters, yet redefined fa and
ce inside?
Why did you define f and c to use two parameters and never passed any?
Why define a function with two arguments that only uses one and should return one that you don't even use?
Did I mention the awful naming of variables? Do you really need both fa and ce?

[o_O]

int main() {
    float choice;
    cout << "This will convert fahrenheit to celsius.";
    cout << "What do you want to start with, enter your number than print enter.\n";
    cout << " 1. Fahrenheit\n";
    cout << " 2. Celsius\n";
    cin >> choice;
    
    if (choice == 1) {
        float fTemp;
        cout << "Input temperature in fahrenheit: ";
        cin >> fTemp;
        cout << toCelcius(fTemp);
    else {
        float cTemp;
        cout << "Input temperature in celcius: ";
        cin >> cTemp;
        cout << toFahrenheit(cTemp);
    }
}

float toCelcius(float fTemp)
{
    return (fTemp-32)/1.8
}

float toFahrenheit(float cTemp);
{
    return (1.8*cTemp)+32;
}

This could be one way to do it by passing variables. You need to define the variable outside of the function in order to pass it too the function.

[Endless]

You also need to define functions <i>before</i> calling them.
Also, one function is enough to do the conversion.

[o_O]

Shh, I'm a Java programmer!
>_>
<_<
I was trying to preserve the original layout too.

I guess this would be a better program then.

float convert(float temp, bool toFahrenheit);

int main() {
    int choice;
    cout << "Choose your conversion:\n1. To fahrenheit\n2. To celcius";
    cin >> choice;
    bool toFahrenheit = (choice == 1);
    cout << "Enter your temperature: ";
    cin >> temp;
    cout << convert(temp, toFahrenheit);
}

float convert(float temp, bool toFahrenheit)
{
    if (toFahrenheit) return (1.8*temp)+32;
    else return (temp-32)/1.8;
}

[Endless]

Close. It won't compile because you forgot to declare a variable
Why make a boolean when you can pass choice directly? Also, you need a couple \n here and there so that it displays better.
I mean:

<font color=lime>lopez@pc9-142</font> <font color=yellow>aks $></font> ./conv2
Choose your conversion:
1. To fahrenheit
2. To celcius1
Enter your temperature: 12
53.6<font color=lime>lopez@pc9-142</font> <font color=yellow>aks $></font> ./conv2
Choose your conversion:
1. To fahrenheit
2. To celcius2
Enter your temperature: 53.6
12<font color=lime>lopez@pc9-142</font> <font color=yellow>aks $></font>

[o_O]

xD
So I did. I guess that's what I get for not testing it before I post it.

[Cruise Control]

Alrightm I finished but it looks totally different. I need to write a function that will round any given number to the 10th decimal place.

//Chris Taylor
//March 15th, 2006
//Intermediate C++, Terminal 6.
//Cube Thingy

#include <iostream.h>
#include <fstream.h>
#include <conio.h>

  //Prototype statements
  void pdescription();
  int choice (int choose);
  float c(float fa);
  float f(float ce);
  void output(float fa, float ce);

 int main()
  {
   //Variable declaration
   float fa=32; //Fahrenheit variable.
   float ce=0; //Celsius variable.
   int choose=0; //Stored for intial choice.

   pdescription();//Calls the function "description"
   choice (choose);//Calls the function "choice"

   if (choose==0)//Determines what is being converted to what.
   {
    f(ce);
   }

   else
   {
    c(fa);
   }

   output(fa, ce);

   getch();
   return 0;
  }

void pdescription()//Prints out program description
{
   cout << "What do you want to start with, enter your number than print enter.\n";
}


int choice(int choose)//Allows user to choose what is being converted to.
{
   cout << " 0. Fahrenheit\n";
   cout << " 1. Celsius\n";
   cin >> choose;
   return choose;
}

float c(float fa)//For converting into fahrenheit.
{
 float ce;
 cout << "Input your celsius vaulue and press\nENTER.\n";
 cin >> ce;
 fa=(1.8*ce)+32; //Formula to convert c to f.
 return fa;
}

float f(float ce)//For converting into celsius.
{
 float fa;
 cout << "Input your fahrenheit vaulue and press\nENTER.\n";
 cin >> fa;
 ce=(fa-32)*(5.0/9.0);//Formula to convert f to c.
 return ce;
}

void output(float fa, float ce)//Prints fahrenheit and celsius value to the screen.
{
 clrscr();
 cout << "Fahrenheit value is: " << fa << endl;
 cout << "Celsius value is: " << ce;
}

[Endless]

I prefer my version that's half as long and does the same xD

And for displaying a fixed number of decimals:
#include &lt;iomanip>

Then just before the cout (only the first time):
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(number_of_decimals_here);


Or for rounding (warning, this comes from the web, in case your teacher checks):

float Round(float Value, int NumPlaces)
   {
   int k, Temp;
   float Factor;
   
   Factor = 1;
   for (k = 0; k < NumPlaces; k++)
      Factor = Factor * 10;
      
   Temp = Value * Factor + 0.5;
   return Temp / Factor;
   }

[Dr Unne]

Alrightm I finished but it looks totally different. I need to write a function that will round any given number to the 10th decimal place.

Is <strong>printf("%.10f", var);</strong> cheating?

[Cruise Control]

My code is lengthy due to the program description.

//Chris Taylor
//March 15th, 2006
//Intermediate C++, Terminal 6.
//Cube Thingy

#include <iostream.h>
#include <fstream.h>
#include <conio.h>


  //Prototype dstatements
  void pdescription();
  int choice (int choose);
  float c(float fa);
  float f(float ce);
  void output(float fa, float ce);

 int main()
  {
   //Variable declaration
   float fa; //Fahrenheit variable.
   float ce; //Celsius variable.
   int choose=0; //Stored for intial choice.

   pdescription();//Calls the function "description"
   choice (choose);//Calls the function "choice"

   if (choose==0)//Determines what is being converted to what.
   {
    f(ce);
   }

   else
   {
    c(fa);
   }

   output(fa, ce);

   getch();
   return 0;
  }

void pdescription()//Prints out program description
{
   cout << "This program will print out two random value for triangle legs, determine the hypotenuse, and quiz the user on the answer.\n";
}


int choice(int choose)//Allows user to choose what is being converted to.
{
   cout << " 0. Fahrenheit\n";
   cout << " 1. Celsius\n";
   cin >> choose;
   return choose;
}

float c(float fa)//For converting into fahrenheit.
{
 float ce=0;
 cout << "Input your celsius vaulue and press\nENTER.\n";
 cin >> ce;
 fa=(1.8*ce)+32; //Formula to convert c to f.
 return fa;
}

float f(float ce)//For converting into celsius.
{
 float fa=32;
 cout << "Input your fahrenheit vaulue and press\nENTER.\n";
 cin >> fa;
 ce=(fa-32)*(5.0/9.0);//Formula to convert f to c.
 return ce;
}

void output(float fa, float ce)//Prints fahrenheit and celsius value to the screen.
{
 clrscr();
 cout << "Fahrenheit value is: " << fa << endl;
 cout << "Celsius value is: " << ce;

}

[Endless]

Did you actually test your code?