SCENARIO 1 : no input parameters, output id line, see the format below.

SCENARIO 2 : two or more command line parameters is an error and the only
output should be "C".

SCENARIO 3 * The command line parameter must be an 8 bit unsigned integer,
if not the output must be "P".
* Given an integer n the output should be the result of the
calculation n!. All calculations should be done using
a standard signed integer ( 32 bit) and the result printed out
using cout then a line feed (\n).
If the calculation proves impossible the output should be "X".

BAKGROUND : note that 0! = 1, 1!=1, 2!=2*1, 3!=3*2*1, 4!=4*3*2*1 .....

I have to use K DEVELOP on linuX i cant get it to work ! ??
*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <iostream>
#include <cstdlib>

using namespace std;

int main(int argc, char *argv[])
{//--- When no parameters MUST print id string in CSV format.
if (argc == 1) // no parameters.
{ cout << "3129072, s3129072@student.rmit.edu.au, Ki Chun Ng"
<< endl ;
return(0) ;
}
if (argc > 2)
{
cout << "C" <<endl;
return(0);
}
int num = atoi(argv[1]);
int result=1;
int inv_EightBit = 0xFF00;

if (argc == 2)
{
if(!num || (num & inv_EightBit))
{
cout << "P"<<endl;
}
else
{
for (int i=1;i<= num ;i++)
{
result = result * i;
}
if (!result)
{
cout<<"X"<<"\n";
}
else
{
cout<<result<<"\n";
}
}

}

//--- START YOUR CODE HERE.

system "pause";
return(0);
}

Please use [code] tags arround you code. It makes it much easier to read.

What exactly is your question?