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

using namespace std;

void Usage(char * progname);
void PrintGreeting(string greeting , int start, int end);
void GetMandN(const char * param,int & start,int & end);

int main(int argc, char * argv[]) {
    string greeting = "hello";
    int greetCount = 1;
    bool reverse = false;
    int charStart = 0;
    int charEnd = -1;

    int i;


    i = 1;
    while (i < argc) {
        if (!strcmp(argv[i],"-h") or !strcmp(argv[i],"--help")) {
	    Usage(argv[0]);
	    i++;
	} else if (!strcmp(argv[i],"-r") or !strcmp(argv[i],"--reverse")){
	    reverse = true;
	    i++;
	} else if (!strcmp(argv[i],"-g") or !strcmp(argv[i],"--greeting"))  {
	    i++;
	    if (i < argc) {
	         greeting = argv[i];
		 i++;
	    } else {
	        cerr <<"Error: " << argv[i-1] << " requires a string" << endl;
	    }
	} else if (!strncmp(argv[i],"-g",2))  {
	    greeting = argv[i];
	    greeting = greeting.substr(2,greeting.size());
	    i++;
	} else if (!strncmp(argv[i],"--greeting=",11))  {
	    greeting = argv[i];
	    greeting = greeting.substr(11,greeting.size());
	    i++;
	} else if (!strcmp(argv[i],"-m"))  {
	    i++;
	    if (i < argc) {
	       greetCount = atoi(argv[i]);
	       i++;
	    } else {
	       cerr << "\t-m requires an integer argument" << endl;
	    }
	} else if (!strcmp(argv[i],"-x"))  {
	    i++;
	    if (i < argc) {
	       GetMandN(argv[i],charStart,charEnd);
	       i++;
	    } else {
	       cerr << "\t-x requires an argument" << endl;
	    }
	} else if (!strncmp(argv[i],"--range=",8))  {
	    string tmp = argv[i];
	    tmp = tmp.substr(8, string::npos);
	    GetMandN(tmp.c_str(),charStart,charEnd);
	    i++;
	} else {
	    cerr << "Unknown argument " << argv[i] << endl;
	    Usage(argv[0]);
	    i++;
	}

    }

 
    // fix a value at the end.
    if (greetCount < 1 or greetCount > 100) {
        cerr << "\tNumber of greetings shold be between 1 and 100, setting to 1"
	     << endl;
        greetCount = 1;
    }

    // perform a task.
    if (reverse) {
        string tmp;
        for (size_t j=greeting.size()-1; j != 0; j--) {
	   tmp += greeting[j];
	}
	tmp += greeting[0];
	greeting = tmp;
    }

    for(i=0;i<greetCount; i++) {
        PrintGreeting(greeting, charStart, charEnd);
    }

    return 0;
}

void Usage(char * progname){
    cout << "Usage: " << progname << endl;
    cout << "\t-h --help: print help, this message" << endl;
    cout << "\t-r --reverse: reverse the greeting" << endl;
    cout << "\t-g  --greeting=string: change the greeting from hello" << endl;
    cout << "\t-m  --multiple=n: Print the greeting n times" << endl;
    cout << "\t-x  --range=a,b: print letters a through b of the greeting"
         << endl;
    cout << "\t\t b=-1 or missing print to the end." << endl;
    return; 
}

void PrintGreeting(string greeting , int start, int end){
    int i;

    if (end == -1 or end > int(greeting.size())) {
       end = greeting.size();
    }

    for (i = start; i<end; i++) {
       cout << greeting[i];
    }
    cout << endl;
    return;
}

void GetMandN(const char * param,int & start,int & end){
    string tmp = param;
   
    size_t pos;

    pos = tmp.find(',');
    if (pos == string::npos) {
        end = -1;
	start = atoi(param);
    } else {
        string first, second;
        first = tmp.substr(0,pos);
	start = atoi(tmp.c_str());
	second = tmp.substr(pos+1,string::npos);
	end = atoi(second.c_str());
    }
    return;
}