main.cpp
#include <stdlib.h>
#include <iostream>
using namespace std;
int SEQ_LENGTH;
int MAX_VALUE;
long long counter = 0;
int* seq;
bool initSeq(char** argv)
{
	SEQ_LENGTH = atoi(argv[1]);
	MAX_VALUE  = atoi(argv[2]);
	if( !SEQ_LENGTH||!MAX_VALUE||SEQ_LENGTH>MAX_VALUE )
		return false;
	
	seq = new int[SEQ_LENGTH];
	for(int j=0;j<SEQ_LENGTH;++j) {
		seq[j] = j+1;
	}
	return true;
}
inline void print()
{
	for(int j=0;j<SEQ_LENGTH;++j) {
		cout << seq[j] << " ";
	}
	cout << endl;
	++counter;
} 
inline bool is_in(int value, int idx)
{
	for(int j=0;j<SEQ_LENGTH;++j)
		if( idx!=j && seq[j]==value )
			return true;
	return false;
}
inline void increase(int idx)
{
	while( is_in(++seq[idx], idx) );
}
inline bool incLeft(int idx)
{
	if( idx<0 )
		return false;
	increase(idx);
	bool result = true;
	if( seq[idx]>MAX_VALUE ) {
		result = incLeft(idx-1);  
		seq[idx] = 0;
		increase(idx);
	}
	return result;
}
void printUsage()
{
	cout << "Lotto: invalid parameters" << endl;
	cout << "Usage: lotto M N" << endl;
	cout << "Where: M <= N;" << endl;
	cout << "  M: Sequence's length" << endl;
	cout << "  N: Max number in the sequence" << endl;
}
int main(int argc, char** argv)
{
	if( argc!=3||!initSeq(argv) ) {
		printUsage();
		return 1;
	}
	while( seq[SEQ_LENGTH-1]<=MAX_VALUE || incLeft(SEQ_LENGTH-1) ) {
		print();
		increase(SEQ_LENGTH-1);
	}
	cout << endl << "Count: " << counter << endl;
	delete [] seq;
	return 0;
}