利用hash_map解决众数问题

#include <fstream>
#include <hash_map>
#include <utility>
using namespace std;
using namespace stdext;

typedef pair <double, int> Num_Pair;

int main()
{
ifstream fin("input.txt");
ofstream fout("output.txt");

hash_map<double, int> hm;
int n;
double num;
double val;
int fre = 0;
hash_map<double, int>::iterator it;

fin >> n;
while (n--)
{
fin >> num;
it = hm.find(num);
if (hm.end() == it)
{
hm.insert(Num_Pair(num, 1));
if (!fre)
{
val = num;
fre = 1;
}
}
else
{
it->second++;
if (it->second > fre)
{
fre = it->second;
val = it->first;
}
}
}

fout << val << endl << fre <<endl;
return 0;
}