#include <iostream>
#include <string.h>
#include <cstdlib>

using namespace std;

void Usage(char*  argv) {
   cout << "Usage " << argv << ":" << endl;
   cout <<"\t-h, --HIGH\t\t Set high value, needs int" << endl;
   cout <<"\t-l, --LOW\t\t Set low value, needs int" << endl;
   cout <<"\t-s\t\t Set skip value, needs int" << endl;
   cout <<"\t?\t\t Help, this message" << endl;
   cout << endl;
   return;
}

int main(int argc, char * argv[]) {

    int lowerLimit = 1,
        upperLimit = 10,
	skipFactor = 1;
    int i;


    i = 1;

    while (i < argc) {
        if (strcmp(argv[i], "?") == 0) {
	    Usage(argv[0]);
	    i++;
        } else if (strcmp(argv[i],"-s")== 0) {
	   i++;
	   if (i < argc) {
	      skipFactor = atoi(argv[i]);
	      if (skipFactor == 0 ) {
	         cout << "Skip value can not be 0" << endl;
		 skipFactor = 1;
	      }
	   } else {
	      cout << "\t-s requires an additional integer argument" << endl;
	   }
	   i++;
	} else if (strcmp(argv[i],"-l") == 0 or strcmp(argv[i],"--LOW")==0) {
	   i++;
	   if (i < argc) {
	      lowerLimit = atoi(argv[i]);
	   } else {
	      cout << "\t-l requires an additional integer argument" << endl;
	   }
	   i++;
	} else if (strcmp(argv[i],"-h") == 0 or strcmp(argv[i],"--HIGH")==0) {
	   i++;
	   if (i < argc) {
	      upperLimit = atoi(argv[i]);
	   } else {
	      cout << "\t-h requires an additional integer argument" << endl;
	   }
	   i++;
        } else {
	   cout << "Unknown Option " << argv[i] << endl;
	   Usage(argv[0]);
	   i++;
	}
    }

    if ((lowerLimit > upperLimit and skipFactor >  0 )
           or (lowerLimit < upperLimit and skipFactor < 0) ) {
        cout <<  " sorry no infinate loops " << endl;

    } else {
        i = lowerLimit;
	if (skipFactor > 0) {
	    while (i <= upperLimit) {
	       cout << i << " " ;
	       i += skipFactor;
    	    }
	} else {
	    while (i >= upperLimit) {
	       cout << i << " " ;
	       i += skipFactor;
    	    }
	}
	cout << endl;
    }
    return 0;
}