提交作业

01-hello.rb

@@ -5,4 +5,4 @@
 
 # ...
 
-puts "(请替换成最后的答案)"
+puts "hello #{your_name}"

02-variable.rb

@@ -7,7 +7,7 @@
 puts "b 是 #{b}"
 
 # ...
+a, b = b, a
 
 puts "a 应该是 2，现在是 #{a}"
 puts "b 应该是 1，现在是 #{b}"
-

03-triangle.rb

@@ -7,5 +7,6 @@
 b = gets
 
 # .....
+s = (a.to_f * b.to_f) / 2
 
-puts "直角三角形的面积是: _________"
+puts "直角三角形的面积是: ____#{s}_____"

04-pizzas.rb

@@ -7,6 +7,8 @@
 people = gets
 
 # .....
+a = pizzas.to_i / people.to_i
+b = pizzas.to_i % people.to_i
 
-puts "每人可分得几片: _________ 片"
-puts "还剩下几片: _________ 片"
+puts "每人可分得几片: _____#{a}____ 片"
+puts "还剩下几片: ____#{b}_____ 片"

05-bmi.rb

@@ -6,12 +6,22 @@
 
 print "请输入您的体重(公斤)，然后按 Enter: "
 weight = gets
+weight = weight.to_f
 
 print "请输入您的身高(厘米)，然后按 Enter: "
 height = gets
-
+height = height.to_f
 # .....
+bmi = weight / ( height ** 2 )
+
+if bmi < 18.5
+  result = "过轻"
+elsif bmi >= 24
+  result = "过重"
+else
+  result = "正常"
+end
 
-puts "您的 BMI 是: _________"
+puts "您的 BMI 是: ____#{bmi}_____"
 
-puts "您的 BMI 结果是: _________(过轻或正常或过重)"
+puts "您的 BMI 结果是: _____#{result}____(过轻或正常或过重)"

06-interger-positive.rb

@@ -3,8 +3,18 @@
 
 print "请输入一个整数，然后按 Enter: "
 x = gets
-
+x = x.to_i
 # ....
 
-puts "这个数是_____ (正数或零或负数)"
-puts "这个数是_____ (偶数或奇数)"
+if x == 0
+  result1 = "零"
+elsif x > 0
+  result1 = "正数"
+else
+  result1 = "负数"
+end
+
+result2 = (x % 2 == 0) ? "偶数" : "奇数"
+
+puts "这个数是___#{result1}__ (正数或零或负数)"
+puts "这个数是__#{result2}___ (偶数或奇数)"

07-abcde.rb

@@ -10,13 +10,25 @@
 
 print "请输入一个整数x，然后按 Enter: "
 x = gets
+x = x.to_i
 
 print "请输入一个整数y，然后按 Enter: "
 y = gets
+y = y.to_i
 
 print "请输入一个整数z，然后按 Enter: "
 z = gets
+z = z.to_i
 
 # ....
+if x > 0
+  if y > 0
+    result = (z > 0) ? "B" : "C"
+  else
+    result = (z > 0) ? "D" : "E"
+  end
+else
+  result = "A"
+end
 
-puts "结果是________(A或B或C或D或E)"
+puts "结果是____#{result}____(A或B或C或D或E)"

08-find-max.rb

@@ -8,7 +8,8 @@
 
 print "请输入一个数字z，然后按 Enter: "
 z = gets
-
 # ....
 
-puts "最大的数是 ________(x或y或z)"
+result = [x, y, z].map(&:to_i).max
+
+puts "最大的数是 ___#{result}_____(x或y或z)"

09-function.rb

@@ -2,14 +2,17 @@
 
 def calculate_area(a, b)
   # ....
+  (a * b) / 2
 end
 
 print "请输入直角三角形的高，然后按 Enter: "
 a = gets
+a = a.to_f
 
 print "请输入直角三角形的底边，然后按 Enter: "
 b = gets
+b = b.to_f
 
 answer = calculate_area(a,b)
 
-puts "直角三角形的面积是: #{answer}"
+puts "直角三角形的面积是: #{answer}"

10-function.rb

@@ -1,6 +1,7 @@
 # 题目: 使用者输入 x,y,z，请输出三个数中最大的数
 
 def find_max(x, y, z)
+  [x, y, z].map(&:to_i).max
 end
 
 print "请输入一个数字x，然后按 Enter: "
@@ -16,4 +17,4 @@ def find_max(x, y, z)
 
 answer = find_max(x,y,z)
 
-puts "最大的数是 #{answer}"
+puts "最大的数是 #{answer}"

11-seven.rb

@@ -4,6 +4,9 @@
 while ( i <= 100 )
 
   # ....
+  if i % 7 == 0
+    puts i
+  end
 
   i+=1
-end
+end

12-sum-even.rb

@@ -6,8 +6,11 @@
 while ( i <= 100 )
 
   # ....
+  if i % 2 == 0
+    total += i
+  end
 
   i+=1
 end
 
-puts total
+puts total

13-nn.rb

@@ -2,10 +2,20 @@
 
 print "请输入数字 N，然后按 Enter: "
 n = gets
+n = n.to_i
 
 # while ( ... )
 #   while ( ...)
 #
 #   end
 # end
 
+i = 1
+while ( i <= n )
+  h = 1
+  while ( h <= n )
+    puts "#{i} * #{h} = #{i * h}" 
+    h += 1
+  end
+  i += 1
+end

14-prime.rb

@@ -1,7 +1,19 @@
 # 输入一个数字 N，请检查是不是质数
 
 def is_prime(n)
-# ....
+  if n < 2
+    return false
+  elsif n == 2
+    return true
+  else
+    for i in 2..n-1
+      if n % i == 0
+        return false
+      else
+        return true
+      end
+    end
+  end
 end
 
 print "请输入数字 N，然后按 Enter: "

15-guess-number.rb

@@ -6,12 +6,13 @@
   print "请猜一个 0~99 的数字 N，然后按 Enter: "
   n = gets
 
-  #puts "太低了，再猜一次"
-  #puts "太高了，再猜一次"
-
   if n.to_i == target
     puts "恭喜猜中啦! "
     break
+  elsif n.to_i > target
+    puts "太高了，再猜一次"
+  else
+    puts "太低了，再猜一次"
   end
 
-end
+end

16-array-sum.rb

@@ -1,11 +1,16 @@
 # 给定一阵列内含数字，输出最大值
 
 def find_max(array)
-  #....
+  m = array[0]
+  for i in 1..((array.length)-1)
+    if array[i] > m
+      m = array[i]
+    end
+  end
+  m
 end
 
 arr = [8, 12, 36, 53, 9, 75, 3, 71, 59, 88]
 
 max = find_max(arr)
 puts "Max is #{max}" # 应该是 88
-

17-array-stats.rb

@@ -1,6 +1,7 @@
 # 使用者不断输入数字存进 Array，最后输出总和、平均、最大值、最小值
 
 arr = []
+total = 0
 
 while (true)
   print "请输入数字，结束请直接按 Enter: "
@@ -12,9 +13,16 @@
   end
 end
 
+for i in arr
+  total += i
+end
+
 puts arr.to_s
+average = total.to_f / arr.length
+max = arr.max
+min = arr.min
 
-puts "总和是 _____"
-puts "平均是 _____"
-puts "最大值是 _____"
-puts "最小值是 _____"
+puts "总和是 __#{total}___"
+puts "平均是 __#{average}___"
+puts "最大值是 ___#{max}__"
+puts "最小值是 ___#{min}__"

18-square.rb

@@ -4,7 +4,11 @@
 
 print "请输入数字 N，然后按 Enter: "
 n = gets
+n = n.to_i
 
+for i in 0..n-1
+  arr << i ** 2
+end
 # ...
 
-puts arr.to_s
+puts arr.to_s

19-filter.rb

@@ -1,9 +1,15 @@
 # 给定一阵列内含数字，输出另一个数组只包含偶数
 
 def filter_even(arr)
-  #...
+  result = []
+  for i in arr
+    if i % 2 == 0
+      result << i
+    end
+  end
+  result
 end
 
 arr =  [7, 68, 42, 46, 9, 91, 77, 46, 86, 1]
 
-puts filter_even(arr).to_s # 应该是 [68, 42, 46, 46, 86]
+puts filter_even(arr).to_s # 应该是 [68, 42, 46, 46, 86]

20-sorting.rb

@@ -2,10 +2,16 @@
 # Hint: 可用 arr.sort 排序，和 arr.uniq 去除重复
 
 def filter_even(arr)
-  #...
+  result = []
+  for i in arr
+    if i % 2 == 0
+      result << i
+    end
+  end
+  result.sort.uniq
 end
 
 arr =  [7, 68, 42, 46, 9, 91, 77, 46, 86, 1]
 
 
-puts "________" # 应该是 [42, 46, 68, 86]
+puts filter_even(arr).to_s # 应该是 [42, 46, 68, 86]

21-selection-sort.rb

@@ -2,11 +2,19 @@
 # https://zh.wikipedia.org/wiki/选择排序
 
 def insertion_sort(arr)
-  #...
+  return arr if arr.length == 0
+  (0..arr.length-1).each do |i|
+    min, index = arr[i], i
+    (i+1..arr.length-1).each do |j|
+      min, index = arr[j], j if arr[j] < min
+      arr[i], arr[index] = arr[index], arr[i]
+    end
+  end
+  arr
 end
 
 arr =  [7, 68, 42, 46, 9, 91, 77, 46, 86, 1]
 
 answer = insertion_sort(arr)
 
-puts answer.to_s # 应该是 [1, 7, 9, 42, 46, 46, 68, 77, 86, 91]
+puts answer.to_s # 应该是 [1, 7, 9, 42, 46, 46, 68, 77, 86, 91]

22-missing.rb

@@ -1,7 +1,12 @@
 # 给定一阵列内含数字，请输出 0~9 中不见的数字
 
 def find_missing(arr)
-  # ...
+  arr.uniq
+  result = []
+  for i in 0..9
+    result << i if !arr.include?(i)
+  end
+  result
 end
 
 answer = find_missing( [2,2,1,5,8,4] )