Function definition

I am truely stumped please help me!
The program will search a file of numbers of type int and write the largest and the smallest numbers to the screen.

#include <iostream.h>
#include <fstream.h>
#include <stdlib.h>
#include <iomanip.h>

void order(int one,int two,int three,int four, int five);

int main()
{
ifstream high2low;

high2low.open("numfile.txt");
if(high2low.fail())
{
cout <<"Input file opening failed.\n";
exit(1);
}

int first, second, third, fourth, fifth;

high2low >> first >>second >>third>>fourth>>fifth;

order(first, second, third, fourth, fifth);

cout << first<<endl;
cout << second<<endl;
cout << third<<endl;
cout << fourth<<endl;
cout << fifth<<endl;

high2low.close();
return 0;
}
void order(int one,int two,int three,int four, int five)
{
int greatest,next;
greatest =
if(one>greatest)

}