change from C to F

Ask the user what conversion he/she wants to do: F to C, C to F, Cm to Feet, Feet to Cm. Use an error handling function.

Test your program with the following data:

C = 0;
F = 0
Feet = 6;
Cm = 100;

This is my program:
#include <iostream.h>
#include <stdlib.h>
#define DEBUG false

float Celsius (float F);
float Fahrenheit (float C);
float Feet (float cm);
float Centimeters (float ft);

int main()
{
      float F, C, ft, cm;

      cout.setf(ios::fixed);
      cout.setf(ios::showpoint);
      cout.precision(2);

      //Get input from the users
      cout <<"Enter the degree of Celsius: ";
      cin >> C;
      cout <<"Enter the degree of Fahrenheit: ";
      cin >> F;
      cout <<"Enter number of Feet: ";
      cin >> ft;
      cout <<"Enter number of Centimeters: ";
      cin >> cm;

      //Output
      cout <<"Degree of Celsius is: "<<Celsius(F)<<endl;
      cout <<"Degree of Fahrenheit is: "<<Fahrenheit(C)<<endl;
      cout <<"Number of feet is: "<<Feet(cm)<<endl;
      cout <<"Number of centimeters is: "<<Centimeters(ft)<<endl;

      system("PAUSE");
      return 0;
}

float Celsius (float F)
/*********************************************************************
Function Name: Celsius
Purpose: Convert number of degree of Fahrenheit to the degree of Celsius.
Arguments: F
Returns: celsius
*********************************************************************/
{
    if (DEBUG)
    {
       cout <<"Degree of Celsius is: "<<Celsius;
       cout <<endl;
    }
    return ((F - 32)/1.8);
}

float Fahrenheit (float C)
/*********************************************************************
Function Name: Fahrenheit
Purpose: Convert number of degree of Celsius to the degree of Fahrenheit.
Arguments: C
Returns: fahrenheit
*********************************************************************/
{
    if (DEBUG)
    {
       cout <<"Degree of Fahrenheit is: "<<Fahrenheit;
       cout <<endl;
    }
    return (9.0/5 * C + 32);;
}

float Feet (float cm)
/*********************************************************************
Function Name: feet
Purpose: Convert number of cm to the number of feet.
Arguments: cm
Returns: feet
*********************************************************************/
{
    if (DEBUG)
    {
       cout <<"Number of feet is: "<<Feet(cm);
       cout <<endl;
    }
    return (cm/30.48);
}

float Centimeters (float ft)
/*********************************************************************
Function Name: feet
Purpose: Convert number of feet to centimeters
Arguments: ft
Returns: cm
*********************************************************************/
{
    if (DEBUG)
    {
       cout <<"Number of centimeters is: "<<Centimeters (ft);
       cout <<endl;
    }
    return (ft*30.48);
}

I just wornder what wrong with my program??