c++ wordlist generator

#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
#include <cstdlib>

int number_of_chars;
char chars_to_use[200];

using namespace std;

ofstream out;

void outputcout(string x, int number_of_chars_left, string separator) {

    char c;

    if(number_of_chars_left==0) {
        cout << x << separator;
        return;
    }

    else {
            for(c=0; c<number_of_chars; c++) {
                outputcout(x+chars_to_use[c], number_of_chars_left-1, separator);
            }
    }
}

void output(string x, int number_of_chars_left, string separator) {

    char c;

    if(number_of_chars_left==0) {
        out << x << separator;
        return;
    }

    else {
            for(c=0; c<number_of_chars; c++) {
                output(x+chars_to_use[c], number_of_chars_left-1, separator);
            }
    }
}

void usage() {
    cerr << "usage: wlg (-l|-w) (no_chars) (chars) [output file]" << endl;
    exit(1);
}


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

    int how_many;
    string separator;

    if(argc<4)
            usage();

    if(!strcmp(argv[1], "-l"))
        separator="\n";
    else if(!strcmp(argv[1], "-w"))
        separator="\r\n";

    how_many=atoi(argv[2]);
    strcpy(chars_to_use, argv[3]);
    number_of_chars=strlen(chars_to_use);

    if(argc==4)
            outputcout("", how_many, separator);

    if(argc==5) {
            out.open(argv[4]);
            output("", how_many, separator);
            out.close();
    }



}