# 第 1 題 - I
public class Main
{
    public static void main(String args[])
    {
        int m = 3;
    	int n = 2;
        for (int i = 0; i < m * n; i++)
        {
            System.out.print("A");
        }
    }
}



# 第 1 題 - II
public class Main
{
    public static void main(String args[])
    {
        int m = 3;
    	int n = 2;
        for (int j = 1; j <= m; j++)
        {
            for (int k = 1; k < n; k++)
            {
                System.out.print("B");
            }
        }
    }
}


# 第 6 題
public class Main
{
    public static void main(String args[])
    {
        int x = 2;
        int y = 5;
        int sum = x + y;
        double average = (double) (sum / 2);
        System.out.println(average);
    }
}



# 第 6 題_修正錯誤後
public class Main
{
    public static void main(String args[])
    {
        int x = 2;
        int y = 5;
        double sum = x + y;
        double average = (double) (sum / 2);
        System.out.println(average);
    }
}



# 第 7 題
  !(!(a && b) || (c || !d))
= !((!a || !b) || (c || !d))
= !(!a || !b) && !(c || !d)
= (!!a && !!b) && (!c && d)
= (a && b) && (!c && d)



# 第 9 題: 用等號後面的物件 (x + x) 指派給等號前面變數 (x) 概念，若是用數學恆等式來推導不會成立
x = x + x = 2x
x = x + x = 2x + 2x = 4x
x = x + x = 4x + 4x = 8x



# 第 15 題
public class Main
{
    public static void main(String args[])
    {
        int num = 10;
        while (num > 1)
        {
            num--;
            System.out.print(num);
        }
    }
}



# 第 19 題
public class Main
{
    public static void main(String args[])
    {
        for (int outer = 0; outer < 3; outer++)
        {
            for (int inner = outer; inner < 3; inner++)
            {
                System.out.print(outer + "" + inner + "_");
            }
        }
    }
}



# 第 20 題 - I
public class Main
{
    public static void main(String args[])
    {
        int x = 1;
        while (x < 6)
        {
            System.out.print(x + " ");
            x = x + 2;
        }
    }
}



# 第 20 題 - II
public class Main
{
    public static void main(String args[])
    {
        int x = 1;
        while (x < 7)
        {
            System.out.print(x + " ");
            x = x + 2;
        }
    }
}



# 第 21 題
public class Main
{
    public static void main(String args[])
    {
        int val = 48;
        int div = 6;
        while ((val % 2 == 0) && div > 0)
        {
            if (val % div == 0)
            {
                System.out.print(val + " ");
            }
            val /= 2;
            div--;
        }
    }
}



# 第 25 題
public class Main
{
    public static void main(String args[])
    {
        for (int j = 1; j <= 5; j++)
        {
            for (int k = 5; k >= j; k--)
            { 
                System.out.print(j + "  ");
            }
            System.out.println();
        }
    }
}



# 第 27 題
public class Main
{
    public static void main(String args[])
    {
        for (int j = 1; j <= 6; j++)
        {
            for (int k = 1; k <= j; k++)
            { 
                System.out.print(" " + k);
            }
            System.out.println();
        }
    }
}



# 第 30 題
public class Main
{
    public static void main(String args[])
    {
        int num = 2574;
        int result = 0;

        while (num > 0)
        {
            result = result * 10 + num % 10;
            num /= 10;
        }
        System.out.println(result);
    }
}



# 第 31 題
public class Main
{
    public static void main(String args[])
    {
        int sum = 0;
        int k = 1;

        while (sum < 12 || k < 4)    // 迴圈沒有中止條件，因為 k < 4 永遠成立
        {
            sum += k;
        }
        System.out.println(sum);
    }
}



# 第 32 題
public class Main
{
    public static void main(String args[])
    {
        for (int inner = 0; outer < n; outer++)
        {
            for (int inner = 0; inner <= outer; inner++)
            { 
                System.out.print(outer + " ");
            }
        }
    }
}