finish programming -exercise hw

01-hello.rb

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

02-variable.rb

@@ -6,7 +6,7 @@
 puts "a 是 #{a}"
 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

@@ -6,6 +6,6 @@
 print "请输入直角三角形的底边，然后按 Enter: "
 b = gets
 
-# .....
+c = (a.to_i) * (b.to_i) / 2
 
-puts "直角三角形的面积是: _________"
+puts "直角三角形的面积是: #{c}"

04-pizzas.rb

@@ -6,7 +6,9 @@
 print "请输入有多少人要吃，然后按 Enter: "
 people = gets
 
-# .....
+a = (pizzas.to_i) / (people.to_i)
 
-puts "每人可分得几片: _________ 片"
-puts "还剩下几片: _________ 片"
+b = (pizzas.to_i) % (people.to_i)
+
+puts "每人可分得几片: #{a} 片"
+puts "还剩下几片: #{b} 片"

05-bmi.rb

@@ -10,8 +10,17 @@
 print "请输入您的身高(厘米)，然后按 Enter: "
 height = gets
 
-# .....
+w = weight.to_f 
+h = height.to_f / 100
+bmi = (w / (h * h)).round(2)
 
-puts "您的 BMI 是: _________"
+if bmi < 18.5
+  bmi_result = "過輕"
+elsif bmi >= 24
+  bmi_result = "過重"
+else bmi >=18.5 || bim <=24
+  bmi_result = "正常"
+end
 
-puts "您的 BMI 结果是: _________(过轻或正常或过重)"
+puts "您的 BMI 是: #{bmi}"
+puts "您的 BMI 结果是: #{bmi_result}"

06-interger-positive.rb

@@ -4,7 +4,19 @@
 print "请输入一个整数，然后按 Enter: "
 x = gets
 
-# ....
+if x.to_i  > 0 
+  inter_result = "正數"
+elsif x.to_i == 0  
+  inter_result = "零"
+else x.to_i <0
+  inter_result = "負數"
+end
 
-puts "这个数是_____ (正数或零或负数)"
-puts "这个数是_____ (偶数或奇数)"
+if x.to_i % 2 == 0
+  this_number = "偶數"
+else
+  this_number = "奇數"
+end
+
+puts "这个数是#{inter_result} (正数或零或负数)"
+puts "这个数是#{this_number} (偶数或奇数)"

07-abcde.rb

@@ -17,6 +17,23 @@
 print "请输入一个整数z，然后按 Enter: "
 z = gets
 
-# ....
+if x.to_i < 0
+  result = "A"
+else 
+  if y.to_i > 0 
+    if z.to_i > 0
+      result = "B"
+    else
+      result = "C"
+    end
+  else
+    if z.to_i > 0 
+      result = "D"
+    else
+      result = "E"
+    end
+  end
+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

@@ -9,6 +9,18 @@
 print "请输入一个数字z，然后按 Enter: "
 z = gets
 
-# ....
+if x > y
+  if x > z
+    find_max = "x"
+  else
+    find_max = "z"
+  end
+else
+  if y > z
+    find_max = "y"
+  else
+    find_max = "z"
+  end
+end
 
-puts "最大的数是 ________(x或y或z)"
+puts "最大的数是 #{find_max}(x或y或z)"

09-function.rb

@@ -1,7 +1,7 @@
 # 题目: 输入直角三角形的宽和高，输出三角形的面积
 
 def calculate_area(a, b)
-  # ....
+  (b.to_i * a.to_i) / 2
 end
 
 print "请输入直角三角形的高，然后按 Enter: "
@@ -12,4 +12,4 @@ def calculate_area(a, b)
 
 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 +1,19 @@
 # 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)
+  if x > y
+    if x > z
+      "x"
+    else
+      "z"
+    end
+  else
+    if y > z
+      "y"
+    else
+      "z"
+    end
+  end
 end
 
 print "请输入一个数字x，然后按 Enter: "
@@ -16,4 +29,4 @@ 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

@@ -2,8 +2,8 @@
 
 i = 1
 while ( i <= 100 )
-
-  # ....
-
+  if i % 7 == 0
+    puts i
+  end
   i+=1
-end
+end

12-sum-even.rb

@@ -5,9 +5,10 @@
 
 while ( i <= 100 )
 
-  # ....
-
+  if i % 2 == 0
+    total += 1
+  end
   i+=1
 end
 
-puts total
+puts total

13-nn.rb

@@ -3,9 +3,28 @@
 print "请输入数字 N，然后按 Enter: "
 n = gets
 
-# while ( ... )
-#   while ( ...)
-#
+# i = 1
+# while ( i <= n.to_i )
+#   j = 1
+#   while ( j <= i)
+#     result = i * j
+#     print "#{j} x #{i} = #{result} "
+#     j += 1
 #   end
+#
+#   print"\n"
+#   i += 1
 # end
 
+i = 0
+j = 0
+n = n.to_i
+while (i <= n )
+  while (j <= n)
+    result = i * j
+    puts "#{i} x #{j} = #{result}"
+    j+=1
+  end
+  i+=1
+  j = 0
+end

14-prime.rb

@@ -1,14 +1,21 @@
 # 输入一个数字 N，请检查是不是质数
 
-def is_prime(n)
-# ....
+def is_prime(num)
+  for i in 2..n/2
+    if n % i == 0
+      false
+    else
+      ture
+    end
+  end
 end
 
+
 print "请输入数字 N，然后按 Enter: "
 n = gets
 
-if is_prime(n.to_i)
-  puts "这是质数"
-else
-  puts "这不是质数"
-end
+# if is_prime(n.to_i)
+#   puts "这是质数"
+# else
+#   puts "这不是质数"
+# end

15-guess-number.rb

@@ -12,6 +12,9 @@
   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

@@ -1,7 +1,7 @@
 # 给定一阵列内含数字，输出最大值
 
 def find_max(array)
-  #....
+  array.max
 end
 
 arr = [8, 12, 36, 53, 9, 75, 3, 71, 59, 88]

17-array-stats.rb

@@ -14,7 +14,12 @@
 
 puts arr.to_s
 
-puts "总和是 _____"
-puts "平均是 _____"
-puts "最大值是 _____"
-puts "最小值是 _____"
+sum = 0
+arr.each do
+  |a| sum += a
+end
+
+puts "总和是#{sum.to_s }"
+puts "平均是 #{sum.to_f/arr.length}"
+puts "最大值是 #{arr.max}"
+puts "最小值是 #{arr.min}"

18-square.rb

@@ -5,6 +5,8 @@
 print "请输入数字 N，然后按 Enter: "
 n = gets
 
-# ...
+for i in 0..n.to_i
+  arr[i] = i * i
+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 = []
+  arr.each do |a|
+    if a % 2 == 0
+      result << a
+    end
+  end
+  return 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)
-  #...
+  arry_result = []
+  arr.each do |result|
+    if result % 2 == 0
+      arry_result << result
+    end
+  end
+  return arry_result
 end
 
 arr =  [7, 68, 42, 46, 9, 91, 77, 46, 86, 1]
 
 
-puts "________" # 应该是 [42, 46, 68, 86]
+puts filter_even(arr).sort.uniq.to_s # 应该是 [42, 46, 68, 86]

21-selection-sort.rb

@@ -2,11 +2,20 @@
 # https://zh.wikipedia.org/wiki/选择排序
 
 def selection_sort(arr)
-  #...
+  (0...arr.length).each do |j|
+    key = arr[j]
+    i = j -1
+    while i >= 0 && arr[i] > key
+      arr[i + 1] = arr[i]
+      i = i - 1
+    end
+    arr[i + 1] = key
+  end
+  arr
 end
 
 arr =  [7, 68, 42, 46, 9, 91, 77, 46, 86, 1]
 
 answer = selection_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)
-  # ...
+  result = []
+  for i in 0..9
+    result << i
+  end
+  missing_number = result - arr
+  return missing_number
 end
 
 answer = find_missing( [2,2,1,5,8,4] )