is a program to calculate the thresholds for transmission receipt using the relation between various physical parameters (distance, effect, propagation model etc.) related to transmissions in ns-2. It has to be compiled by the user. This is not a difficult task, but could pose some challenges as the compiler over time is updated and no longer accepts the outdated c-code of outdated versions of ns-2.

Trying to do g++ will break if trying this with a reasonably updated version of Ubuntu and the g++ compiler (v4.3.3) in combination with ns-2.33. Thus, to make it work, delete the line that reads
#include <iostream.h>

and write these three lines there instead:
#include <iostream>
#include <cstring>
using namespace std;

Then try to compile with g++ again:
g++ -o threshold