currency convertor.cxx

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<cmath>
using namespace std;
inline void keep_window_open() { char ch; cin>>ch; }
int main () {
double chinese_rmb;
double usa_dollar;
double european_euro;
int userinput;
constexpr double rmb_to_usd=0.16;
constexpr double rmb_to_euro=0.13;
constexpr double usd_to_euro=0.85;
cout<<"Welcome to my currency convertor.\n";
cout<<"This convertor supports USD,RMB,and the EURO.\n";
cout<<"If converting usd to rmb press 1\n";
cout<<"If converting rmb to usd press 2\n";
cout<<"If converting usd to euro press 3\n";
cout<<"If converting euro to usd press 4\n";
cout<<"If converting rmb to euro press 5\n";
cout<<"If converting euro to rmb press 6\n";
cin>>userinput;
switch (userinput) {
case 1: cout<<"Enter in the amount of USD you wish to convert\n";
cin>>usa_dollar;
cout<<"You now have ";
cout<<usa_dollar/rmb_to_usd;
cout<<" Chinese RMB";
break;
case 2: cout<<"Enter in the amount of RMB you wish to convert\n";
cin>>chinese_rmb;
cout<<"You now have ";
cout<<chinese_rmb*rmb_to_usd;
cout<<" American USD";
break;
case 3:
cout<<"Enter in the amount of USD you want to convert\n";
cin>>usa_dollar;
cout<<"You now have "<<usa_dollar*usd_to_euro<< " European EURO";
break;}
}