leetcode intToRoman

#include<iostream>
#include<unordered_map>
#include<string>
using namespace std;
string intToRoman(int num)
{
if(num>3999||num<1)
return string("the num is out of range");
unordered_map<int,string> map;
map[1000]="M";
map[900]="CM";
map[500]="D";
map[400]="CD";
map[100]="C";
map[90]="XC";
map[50]="L";
map[40]="XL";
map[10]="X";
map[9]="IX";
map[5]="V";
map[4]="IV";
map[1]="I";
string result;
unordered_map<int,string>::iterator iter=map.begin();
while(num>0)
{
int i=iter->first;
int count=num/i;
num%=i;
for(;count>0;--count)
{
result+=map[i];
}
++iter;
}
return result;
}
int main()
{
cout<<intToRoman(1000)<<endl;
cout<<intToRoman(900)<<endl;
cout<<intToRoman(500)<<endl;
cout<<intToRoman(400)<<endl;
cout<<intToRoman(100)<<endl;
cout<<intToRoman(90)<<endl;
cout<<intToRoman(50)<<endl;
cout<<intToRoman(40)<<endl;
cout<<intToRoman(10)<<endl;
cout<<intToRoman(9)<<endl;
cout<<intToRoman(5)<<endl;
cout<<intToRoman(4)<<endl;
cout<<intToRoman(1)<<endl;
cout<<intToRoman(1234)<<endl;
return 0;
}