triangle.cpp

/*
 * Author: Jeremy Yen Date: 2013.10.10
 * http://oj.sslab.cs.nthu.edu.tw/problems/11
 *
 */

#include <iostream>
#include <sstream>
using namespace std;

int input_n;

string genStar( int n )
{
	stringstream ss;
	for( int i = 0; i < n; i++ )
		ss << '*';
	return ss.str();
}

string genSpace( int n )
{
	stringstream ss;
	for( int i = 0; i < n; i++ )
		ss << ' ';
	return ss.str();
}

string genTriangle( int layer )
{
	stringstream ss;
	for( int i = 1; i <= layer; i++ )
	{
		int star_count = 2 * i - 1;
		int space_count = ((2 * (input_n + 2) - 1) / 2);
		space_count -= (int)(star_count / 2 );

		ss << genSpace(space_count)
		   << genStar(star_count) 
		   << genSpace(space_count)
		   << endl;
	}
	return ss.str();
}

int main()
{
	cin >> input_n;

	for( int i = 3; i <= ( input_n + 2 ); i++ )
	{
		cout << genTriangle(i);
	}
	return 0;
}