//	Ex760.cc

//	Sec. 7.6 of lecture
//		main as function with parameters and return value
//			input parameters per command line
//
//			see also:  man atoi
//
//		a real C++ solution, see Stroustrup, p.126 (§6.1.7)

#include <iostream.h>
#include <stdlib.h>			// needed for atoi, exit

void spass(const int);			// Declaration of spass()

int main(const int argc, const char* argv[])	// a function has return value int by default
{
 int n;
 
 cout << endl;
 cout << "This is code " << argv[0] << endl;
 
 if (argc > 1)				// at least one argument
  {
   n = atoi(argv[1]);			// atoi : ACSII to Integer
  }
 else					// standard input
  {
   cout << " Eingabe n : ";
   cin  >> n;
   cout << endl;
  }
  
 spass(n);				// Call spass()
 
 cout << endl;
// 		We play around with exit, abort, return
 
 return 0;				// default return value is 0
}


void spass(const int n)
{
 if (n<0) 				// usage of exit()
 {
   cout << "Fatal Error in spass(): n = " << n << " < 0" << endl; 
   exit(-10);				// choose an error code
 }

 cout << "Jetzt schlägt's aber " << n << endl;
 return;
}