submit week4 assignments

block_function.rb

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+# (6) Create a program block_function.rb.  
+# It should have a function do_calc that calls a block using a yield statement.  
+# The yield statement will pass the numbers 7 and 9 to a block, and then will print out the result.  
+# Call the do_calc function twice in your program. 
+# The first time, pass a block that adds the two numbers. 
+# The second time, pass a block that multiplies the two numbers.  Your program should print out 16 and 63. 
+
+def do_calc
+    yield 7, 9
+end 
+
+do_calc do |a, b|
+   puts  a + b
+end
+
+do_calc do |a, b|
+    puts a * b
+end    

divisible.rb

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+# (1) Write a method that returns in an array all the numbers between 1 and 100 that are divisible by 2 or 3 or 5. 
+# Then call the method in your program and print out what it returns.  Call the program divisible.rb.
+
+def divisible
+    array= []
+    i = 1
+
+    while i >=1 and i <= 100
+        array.push(i) if (i % 2 == 0 || i % 3 == 0 || i % 5 == 0)
+        i += 1
+    end    
+
+    array.each do |item|
+        puts item
+    end
+end
+
+divisible
+

hangman.rb

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+#(2) Write a program hangman.rb that contains a function called hangman.  
+# The function's parameters are a word and an array of letters.  
+# It returns a string showing the letters that have been guessed.  
+# Call the function from within your program so that you know that it works.
+
+def hangman(string, array)
+    result = "_" * string.length
+    temp = string.downcase
+    array.each do |item|
+        item = item.downcase
+        while temp.index(item) do
+            num = temp.index(item)
+            result[num] = item
+            temp[num] = "_"
+        end    
+    end
+   result
+end    
+
+puts hangman("bob", ["b"])
+puts hangman("alphabet", ["a", "h"])
+puts hangman("mingkIng", ["M", "i", "g"])
+
+# Another student did it in a very efficient way
+# def hangman(string, array)
+#    result = ""
+#    string.each_char do |char|
+#       result += array.include?(char)? char : "_"
+#    end
+# result
+# end 

hash_to_array.rb

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+#(3) Write a program that collects 5 keys and 5 values from the user, and stores them in a hash.  
+# Write a function that accepts the hash as optional parameters and prints out an array of keys and an array of values.  
+# Call the function within your program so you know it works. 
+# (Question: Can you find online information on Ruby hash methods that will help with this function?)  
+# Call this program hash_to_array.rb.
+
+def hash_to_array(hash={})
+
+    def ask(question, kind="string")
+        print question + " "
+        answer = gets.chomp
+        answer = answer.to_i if kind == "number"
+        return answer
+    end
+
+    if hash.empty?    
+        hash = {}
+        5.times do |num|
+            key = ask("enter key#{num+1}: ")
+            value = ask("enter value#{num+1}: ")
+            hash[key] = value
+        end
+    end
+
+    puts "Array of keys: #{hash.keys}"
+    puts "Array of values: #{hash.values}"
+end
+
+puts "Result with parameter send in: "
+hash_to_array({"a" => "aaa", "b" => "bbb"})
+
+puts "\nResult without parameter send in:"
+hash_to_array()

sort_blocks.rb

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+#(5) The ruby array sort method can use a block to sort various arrays.  The block
+# must compare between two elements of the array, a and b.  If a<b, it should evaluate to -1.
+# If a==b, it should evaluate to 0.  And if a>b, it should evaluate to 1. 
+# Here is the start of a program, which you should call sort_blocks.rb.
+
+# Add to this program. Add additional calls to book_array.sort that pass blocks.  
+# For your first call to sort, pass a block so that the array is sorted in order of title, and print out the array.
+# For your second call to sort, pass a block so that the array is sorted in order of copies, and print out the array.
+
+class Book
+  attr_reader :author, :title, :count
+  def initialize(author,title,count)
+    @author = author
+    @title = title
+    @count = count
+  end
+  def to_s
+    "author: #{author} title: #{title} count: #{count}"
+  end
+end
+
+book_array = []
+book_array.push(Book.new("Beatrice Potter","Peter Rabbit",25))
+book_array.push(Book.new("Henry Fielding","Tom Jones",12))
+book_array.push(Book.new("Bob Woodward","All the President's Men",30))
+
+puts "Sorting alphabetically by author"
+
+new_array = book_array.sort do |a,b|
+  author1 = a.author.downcase
+  author2 = b.author.downcase
+  author1 <=> author2
+  # if author1 > author2
+  #   1
+  # elsif author1 < author2
+  #   -1
+  # else
+  #   0
+  # end
+end
+puts new_array
+
+puts "\nSorting alphabetically by titles" 
+sort_array_by_title = book_array.sort do |a, b|
+    title1 = a.title.downcase
+    title2 = b.title.downcase
+    title1 <=> title2
+end
+puts sort_array_by_title
+
+puts "\nSorting by copies in ascending order" 
+sort_array_by_copies = book_array.sort do |a, b|
+    copies1 = a.count
+    copies2 = b.count
+    copies1 <=> copies2
+end
+puts sort_array_by_copies

sums.rb

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+#(4) Create a program sums.rb with two classes.
+#(a) a class called Sum1 with an initialize method that takes two parameters 
+# and sets the instance variable total to the sum of the two. Include a line at the top of the class: attr_accessor :total
+
+#(b) a class called Sum2 with an initialize method that takes two parameters a and b 
+#and sets the instance variable a to the parameter a and the instance variable b to the parameter b. 
+#Create a method new_total inside Sum2 that returns the sum of the instance variables a and b.
+
+#(c) In the mainline program, create instances of Sum1 and Sum2, passing 5 and 6 as parameters on the new statement.  
+# Print out the total for Sum1.  Print out the new_total for Sum2.
+
+class Sum1
+    attr_accessor :total
+    def initialize(param1, param2)
+        @total = param1 + param2
+    end    
+end   
+
+class Sum2
+    def initialize(a, b)
+        @a = a
+        @b = b
+    end        
+    def new_total
+        @a + @b
+    end        
+end   
+
+sum1 = Sum1.new(5, 6)
+sum2 = Sum2.new(5, 6)
+
+puts sum1.total
+puts sum2.new_total