C++ program for temperature conversion

#include<iostream.h>
#include<conio.h>
#include<stdlib.h>
void main(){
float ct,kt,ft,rt;
char choice;
while(1){
clrscr();
cout<<"Temprature Conversion Program\n Input Temprature in one of Following scale\n- C\nK\nF\nR\nE(eixt)\n Enter Your Choice"<<endl;
cin>>choice;
switch (choice){
case 'c': case 'C': cout<<"Enter Temprature in Celsius"<<endl;
cin>>ct;
kt=273+ct;
ft=((9/5.0)*ct)+32;
rt=((4/5.0)*ct);
break;
case 'k': case 'K': cout<<"Enter Temprature in Kelvin"<<endl;
cin>>kt;
ct=kt-273;
ft=((9/5.0)*(kt-273))+32;
rt=((4/5.0)*(kt-273));
break;
case 'f': case 'F': cout<<"Enter Temprature in Fahrenhiet"<<endl;
cin>>ft;
ct=(5/9.0)*(ft-32);
kt=((5/9.0)*(ft-32))+273;
rt=((4/9.0)*(ft-32));
break;
case 'r': case 'R': cout<<"Enter Temprature in Rumer"<<endl;
cin>>rt;
ct=(5/4.0)*rt;
kt=((5/4.0)*rt)+273;
ft=((9/4.0)*rt);
break;
case 'e': case 'E': exit(0);
default : cout<<"Wronf Input"<<endl;
getch();
}
cout<<"Temprature in Different Scale\n Celius = "<<ct<<endl<<"Kelvin = "<<kt<<endl<<"Fahrenhiet = "<<ft<<endl<<"Rumer = "<<rt<<endl;
getch();
}
}