I have to write a program that takes temperature in celsius (if in farenheit, it converts it to celsius) along with the windspeed and calculates the windchill. I have the program written but I can't figure out what I'm doing wrong in lines 63 and 75. Any help would be appreciated!

#include <iostream>
using namespace std;

void FtoC(); //Gets input in farenheit, makes conversion to Celsius, displays results.

void TEMPinC (); //Asks user for the temperature in Celsius.

void WINDSPEED (double SPEED);
//Asks user for the wind speed in m/sec.

void WINDCHILL(double WINDSPEED, double TEMPERATURE, double WINDCHILL_INDEX);
//Calculates the windchill from the input information.
void WINDCHILL_OUT();
//Outputs the results of the conversion.

int main()
{
char repeat;

cout << "This program will take the wind speed\n"
<< "and the temperature and find the windchill index.\n\n"
<< "wind speed is in m/sec, while\n"
<< "temperature is in degrees Celsius or Farenheit.\n\n";

do{
WINDCHILL_OUT();
cout << "Would you like to make another conversion?\nPlease enter y or n. ";
cin >> repeat;
}while(repeat=='y');

cout << "\nThank you and goodbye.\n";

system("PAUSE");
return 0;
}

void FtoC(double FARENHEIT, double& TEMPERATURE)
{
int which;

cout << "\nPlease enter 1 to convert celsius and\nenter 2 to convert farenheit. ";
cin >> which;
while(which !=1 && which !=2)
{
cout << "Please enter 1 or 2. ";
cin >> which;
}
if(which==1)
{
cout << "Please enter the temperature in farenheit followed by enter\n";
cin >> FARENHEIT;
TEMPERATURE = (FARENHEIT-32)*(5/9);
}

else
TEMPinC();
}

void TEMPinC()
{
cout << "Please enter the temperature in farenheit followed by enter\n";
cin >> TEMPERATURE;
}

void WINDSPEED (double SPEED)
{
cout << "\nPlease enter the windspeed in m/sec.\n";
cin >> SPEED;
}

void WINDCHILL(double WINDSPEED, double TEMPERATURE, double WINDCHILL_INDEX)
{
WINDCHILL_INDEX = 13.12 + (0.6215*TEMPERATURE) - (11.37 * (pow(WINDSPEED,0.16))
+ (0.3965 * TEMPERATURE * (pow(WINDSPEED,0.016));
}


void WINDCHILL_OUT(double WINDSPEED, double TEMPERATURE, double WINDCHILL_INDEX)
{
cout << "\nWith a temperature of " << TEMPERATURE << " and a windspeed of\n"
<< WINDSPEED << " the windchill index is " << WINDCHILL_INDEX << " degrees celsius\n\n";
}