package digitGroup;

import java.util.Stack;

/**
 * 10Áø¼ö¸¦ ÀԷ¹޾Æ, õ(1000)ÀÚ¸® ±¸ºÐÀÚ¸¦ Ãß°¡ÇÏ´Â ÇÁ·Î±×·¥.
 */
public class DigitGroupAsInt {

	public static void main(String args[]) {
		int loopCount = 1000000;
		for(int idx=0; idx<10; idx++) {
			long startMilliTime = System.currentTimeMillis();
			benchmark(10, 10, loopCount);
			long endMilliTime = System.currentTimeMillis();
			System.out.println( loopCount + ";" + (endMilliTime - startMilliTime));
			loopCount += 1000000;
		}
	}
	
	private static void benchmark(int startNum, int interval, int loopCount) {
		int inputNumber = startNum; 
		for(int cnt=0; cnt<loopCount; cnt++) {
			convert(inputNumber);
			inputNumber += interval;
		}
	}

	private static String convert(int number) {
		final int DECIMAL_NUMBER = 10;
		final char THOUSANDS_SEPARATOR = ',';

		Stack<Character> digitStack = new Stack<Character>();
		StringBuilder sb = new StringBuilder();

		int quotient, spare, count = 0;
		do {
			// ¸ò°ú ³ª¸ÓÁö °è»ê
			quotient = number / DECIMAL_NUMBER;
			spare = number % DECIMAL_NUMBER;

			// ¸òÀ» n ¿¡ ÀçÇÒ´ç, ³ª¸ÓÁö´Â ½ºÅÿ¡ Ãß°¡
			number = quotient;
			digitStack.push(Character.forDigit(spare, 10));

			// 3°³ÀÇ ¼ýÀÚ¸¦ Ãß°¡Çß´Ù¸é, ±¸ºÐÀÚ¸¦ ¹öÆÛ¿¡ Ãß°¡
			if (++count == 3 && quotient > 0) {
				digitStack.push(THOUSANDS_SEPARATOR);
				count = 0;
			}

		} while (quotient > 0);

		// ½ºÅÿ¡ ÀúÀåµÈ ¼ýÀÚ¸¦ ²¨³» ¹®ÀÚ¿­ ¹öÆÛ¿¡ Ãß°¡
		while (!digitStack.empty()) {
			sb.append(digitStack.pop());
		}

		return sb.toString();
	}

}