Feet ,inç ve Cm Dönüşümleri C++

1 feet = 30,48 cm && 1 cm = 0,0328

1 inç = 2.54 cm && 1 cm = 0.3937

#include "iostream"
#include "locale.h"

using namespace std;

void feet_cevir();
void inc_cevir();
void feetcm();
void cmfeet();
void inccm();
void cminc();


int feet,inc,cm;
int main()
{
	setlocale(LC_ALL, "Turkish");
	cout << "~~Uzunluk Birimi Çevirme~~" << endl;
	cout << "1)feet-cm " << endl;
	cout << "2)inç-cm" << endl;
	cout << "\nislemi seç" << endl;
	int secim;
	cin >> secim;

	switch (secim)
	{
	case 1:
		feet_cevir();
		break;
	case 2:
		inc_cevir();
		break;
	default:
		break;
	}
	system("pause");
	return 0;
}

void feet_cevir(){
	cout << "Feet - Cm işlemleri" << endl;
	cout << "1) feet-cm" << endl;
	cout << "2) cm-feet" << endl;
	cout << "\nislemi seç" << endl;
	int feet_secim;
	cin >> feet_secim;

	switch (feet_secim)
	{
	case 1:
		feetcm();
		break;
	case 2:
		cmfeet();
		break;
	default:
		break;
	}
}

void inc_cevir(){
	cout << "inc - Cm işlemleri" << endl;
	cout << "1) inc-cm" << endl;
	cout << "2) cm-nc" << endl;
	cout << "\nislemi seç" << endl;
	int inc_secim;
	cin >> inc_secim;

	switch (inc_secim)
	{
	case 1:
		inccm();
		break;
	case 2:
		cminc();
		break;
	default:
		break;
	}

	
}


void feetcm(){
	cout << "\feet - cm dönüştürücüsü" << endl;
	cout << "feet : ";
	cin >> feet;
	if (feet < 0)
		cout << "hatalı giriş.";
	else
	{
		cm = 0.0328*feet;
		cout << "cm :  " << cm << endl;
	}
	
}

void cmfeet(){
	cout << "\cm - feet dönüştürücüsü" << endl;
	cout << "cm : ";
	cin >> cm;
	if (cm < 0)
		cout << "hatalı giriş.";
	else
	{
		feet = 39.48*cm;
		cout << "feet :  " << feet << endl;
	}
	
}


void inccm(){
	cout << "\inc - cm dönüştürücüsü" << endl;
	cout << "inc : ";
	cin >> inc;
	if (inc < 0)
		cout << "hatalı giriş.";
	else
	{
		cm = 0.393*inc;
		cout << "cm :  " << cm << endl;
	}

}

void cminc(){
	cout << "\cm - feet dönüştürücüsü" << endl;
	cout << "cm : ";
	cin >> cm;
	if (cm < 0)
		cout << "hatalı giriş.";
	else
	{
		inc = 2.54*cm;
		cout << "inc :  " << inc << endl;
	}
}