编写一段程序，读入正数N，然后计算并显示前N个奇数整数的和。

import java.util.Scanner;

public class OddSum {
    public static void main(String[] args) {
        int odd = 1, sum = 0, n;
        Scanner reader = new Scanner(System.in);
        n = reader.nextInt();
        for(int i = 0; i < n; i++, odd += 2)
            sum += odd;
        System.out.printf("%d\n", sum);
    }
} /* Output
4
16
*/