Java打印九九乘法表代码详情

下面是Java打印九九乘法表的完整攻略：

1. 算法思路

九九乘法表的每一行都有规律，可以利用双重嵌套循环，外层循环控制每一行，内层循环控制每一列，通过打印表格中的乘积结果实现。

2. 代码示例

以下是一段Java代码，可以打印九九乘法表：

public class MultiplicationTable {
    public static void main(String[] args) {
        for(int i=1; i<=9; i++) { //外层循环控制每一行
            for(int j=1; j<=i; j++) { //内层循环控制每一列
                System.out.print(j + " * " + i + " = " + i*j + "\t"); //输出乘积结果
            }
            System.out.println(""); //换行
        }
    }
}

运行该代码，会得到九九乘法表的结果：

1 * 1 = 1   
1 * 2 = 2   2 * 2 = 4   
1 * 3 = 3   2 * 3 = 6   3 * 3 = 9   
1 * 4 = 4   2 * 4 = 8   3 * 4 = 12  4 * 4 = 16  
1 * 5 = 5   2 * 5 = 10  3 * 5 = 15  4 * 5 = 20  5 * 5 = 25  
1 * 6 = 6   2 * 6 = 12  3 * 6 = 18  4 * 6 = 24  5 * 6 = 30  6 * 6 = 36  
1 * 7 = 7   2 * 7 = 14  3 * 7 = 21  4 * 7 = 28  5 * 7 = 35  6 * 7 = 42  7 * 7 = 49  
1 * 8 = 8   2 * 8 = 16  3 * 8 = 24  4 * 8 = 32  5 * 8 = 40  6 * 8 = 48  7 * 8 = 56  8 * 8 = 64  
1 * 9 = 9   2 * 9 = 18  3 * 9 = 27  4 * 9 = 36  5 * 9 = 45  6 * 9 = 54  7 * 9 = 63  8 * 9 = 72  9 * 9 = 81  

3. 示例说明

示例一

输入：

public class MultiplicationTable {
    public static void main(String[] args) {
        for(int i=1; i<=4; i++) {
            for(int j=1; j<=i; j++) {
                System.out.print(j + " * " + i + " = " + i*j + "\t");
            }
            System.out.println("");
        }
    }
}

输出：

1 * 1 = 1   
1 * 2 = 2   2 * 2 = 4   
1 * 3 = 3   2 * 3 = 6   3 * 3 = 9   
1 * 4 = 4   2 * 4 = 8   3 * 4 = 12  4 * 4 = 16  

说明：该示例主要演示了如何自定义九九乘法表的规模，这里我们把它设置为输出前4行，结果符合我们的预期。

示例二

输入：

public class MultiplicationTable {
    public static void main(String[] args) {
        for(int i=1; i<=9; i++) {
            for(int j=1; j<=i; j++) {
                System.out.printf("%2d * %-2d = %2d ", j, i, j*i);
            }
            System.out.println("");
        }
    }
}

输出：

 1 * 1  =  1 
 1 * 2  =  2  2 * 2  =  4 
 1 * 3  =  3  2 * 3  =  6  3 * 3  =  9 
 1 * 4  =  4  2 * 4  =  8  3 * 4  = 12 4 * 4  = 16 
 1 * 5  =  5  2 * 5  = 10 3 * 5  = 15 4 * 5  = 20 5 * 5  = 25 
 1 * 6  =  6  2 * 6  = 12 3 * 6  = 18 4 * 6  = 24 5 * 6  = 30 6 * 6  = 36 
 1 * 7  =  7  2 * 7  = 14 3 * 7  = 21 4 * 7  = 28 5 * 7  = 35 6 * 7  = 42 7 * 7  = 49 
 1 * 8  =  8  2 * 8  = 16 3 * 8  = 24 4 * 8  = 32 5 * 8  = 40 6 * 8  = 48 7 * 8  = 56 8 * 8  = 64 
 1 * 9  =  9  2 * 9  = 18 3 * 9  = 27 4 * 9  = 36 5 * 9  = 45 6 * 9  = 54 7 * 9  = 63 8 * 9  = 72 9 * 9  = 81 

说明：该示例主要演示了如何使用printf方法增强格式化输出，通过指定输出的长度来使得乘积垂直对齐。