C++ :: How To Make A Program That Converts Input Numbers Into Equivalent Words

I've reached a point in "Jumping into C++" where I need to make a program that converts input numbers into their word equivalent.

So far I've made it work for numbers 0-9999. I've tried implementing 10000-99999 but there are problems with the order of the words printed (57865 would print fifty thousand seven thousand eight hundred sixty five). But besides that, the program is absolutely enormous (for me) and I'm wondering if it can be shortened. Keep in mind I can only use loops and if statements so far. Here it is:

Code:

#include <iostream>
#include <string>
void extras(int e);
void digits(int x);
void tens(int xx);
void hundreds(int xxx);
void thousands(int xxxx);
//void tens_of_thousands(long xxxxx);

[Code]....