Fahrenheit-Celsius converter

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

void c_to_f(void);
void f_to_c(void);

void
 main(void)
{
	int choice;
	char again;
	do
	{
		system("CLS");
		
		cout << setw(10) <<" "<< "What conversion would you like to make?\n";	// menu
		cout << setw(20) <<" "<< "1. Celsius to Fahrenheit\n\n";					// make a choice which function to use.
		cout << setw(20) <<" "<< "2. Fahrenheit to celsius\n\n";
		cin >> choice;

			switch(choice)										// go to chosen function.
			{
				case 1 :
					{
						c_to_f();
						break;
					}
				case 2 : 
					{
						f_to_c();
						break;
					}
				default :
				{
					cout << setw(10) <<" "<< "you must enter 1 or 2  "<< endl ;		// validate and correct input of function choice.
				
				}
						
						
			}
			
			

			cout << setw(10) <<" "<< "Do you wish to do another conversion? y for yes, n for no  ";	// rerun loop on y for yes
			cin >> again;
	}while (again == 'Y' || again =='y');
	
}


void c_to_f(void)
{
	system("CLS");								// clear screen for function data.
	int temp,fahrenheit;

	cout << "\n\n\n";
	cout << setw(10) <<" "<< "Enter the temperature in whole degrees celsius. \a";
	cin >> temp;

	fahrenheit = ((temp * 9) / 5) + 32;
	cout << endl << setw(10) <<" "<< temp << " degrees celsius is " << fahrenheit << " degrees fahrenheit \a\n\n\n";
}

void f_to_c(void)
{
	system("CLS");								// clear screen for function data.
	int temp,celsius;

	cout << "\n\n\n";
	cout << setw(10) <<" "<< "Enter the temperature in whole degrees fahrenheit.  \a";
	cin >> temp;

	celsius = ((temp - 32) * 5) / 9;
	
	cout << endl <<setw(10) <<" "<< temp << " degrees fahrenheit is " << celsius << " degrees celsius \a\n\n\n";
}