1 object Test extends App
2 {
3 def printMultiTable()
4 {
5 var i = 1
6 while (i < 10)
7 {
8 var j = 1
9 while (j <= i)
10 {
11 val prod = i * j
12 if (j != 1) print(" ")
13 val str = s"$j * $i = $prod"
14 val k = str.length
15 // while (k <= 10)
16 // {
17 // print(" ")
18 // k = k + 1
19 // }
20 if (k < 10)
21 {
22 print(" " * (10 - k))
23 }
24 print(str)
25 j += 1
26 }
27 println()
28 i += 1
29 }
30 }
31
32 // printMultiTable()//打印测试
//返回第i行第j列的单个乘法式子
33 def multiExpression(i: Int, j: Int): String =
34 {
35 val res = i * j
36 s"$j * $i = $res "//注意j在前
37 }
38 //乘法表，至第i行第j列
39 def multiTable(i: Int, j: Int, str: String): String =
40 {
41 if (i <= 0 && j <= 0)
42 {
43 str
44 }
45 else if (j == 1)
46 {
if(i == 1)
multiExpression(1, 1) + str
else
47 multiTable(i - 1, i - 1, "\n" + multiExpression(i, 1) + str )//在后面追加打印出的单个乘法式子，注意换行
48 }
49 else
50 {
51 multiTable(i, j - 1, multiExpression(i, j) + str)
52 }
53 }
54
55 println(multiTable(4, 4, ""))//打印测试
56
//返回第i行，从该行的第1到第j个式子； 一行 = 前j-1个式子 + 第j个式子
57 def multiLine(i: Int, j: Int, str: String): String =
58 {
59 if (j == 0)
60 {
61 str
62 }
63 else
64 {
65 multiLine(i, j - 1, multiExpression(i, j) + str)
66 }
67 }
68 //利用子表“加上”当前行的思维，递归
69 def multiTable2(i: Int): String =
70 {
71 if (i == 1)
72 {
73 "1 * 1 = 1 "
74 }
75 else
76 {
77 multiTable2(i - 1) + "\n" + multiLine(i,i,"")
78 }
79
80
81 }
82
83 println(multiTable2(3))
84 }
