kotp · July 12, 2018 02:49 · Nov 6, 2014 · Apr 18, 2012 · Apr 18, 2012
diff --git a/w1e6_a1.rb b/w1e6_a1.rb
@@ -1,6 +1,6 @@
 
 def convert(temperature_in_F)
-  (temperature_in_F - 32) / 1.8
+  (temperature_in_F - 32) / 1.8 # This solution can cause problems.  Why?
 end
 
 puts "%.2f" % convert(-40) # => -40.00
diff --git a/readme.txt b/readme.txt
@@ -0,0 +1,4 @@
+This is a collection of exercises, and answers.
+
+Filenames will be in the form of w1e1.rb.
+Answers will be w1e1a1.rb with subsequent 'best answers' being numbered consecutively.
diff --git a/w1e1.md b/w1e1.md
@@ -0,0 +1,15 @@
+Exercise1. Before executing the code given below, guess the results. Next, execute the code. Did you get it right? If you did not get it right, can you think of why?
+
+Discuss your first guess and what you got when running the code.
+Goal: Understanding operator precedence and association.
+
+```ruby
+y = false
+z = true
+x = y or z
+puts x
+(x = y) or z
+puts x
+x = (y or z)
+puts x
+```
diff --git a/w1e1_a1.md b/w1e1_a1.md
@@ -0,0 +1,11 @@
+
+```ruby
+y = false          # simply an assignment
+z = true           # simply an assignment
+x = y or z         # x is assigned false though true is returned for the line
+puts x             # prints false
+(x = y) or z       # x is again assigned false while the line returns true
+puts x             # prints false
+x = (y or z)       # (y or z) returns true, and that result is assigned to x
+puts x             # prints true as the parentheses gives precedence to or
+```
diff --git a/w1e2.md b/w1e2.md
@@ -0,0 +1,6 @@
+Read the sprintf documentation and the % documentation in the String class and 
+figure out the output being printed by of this Ruby code.
+
+```ruby
+puts "%05d" % 123
+```
diff --git a/w1e2_a1.md b/w1e2_a1.md
@@ -0,0 +1,12 @@
+sprintf format_string
+
+%[flags][width][.precision]type
+
+For %05d:
+
+flags:
+  0 = Pad with zeros, not spaces.
+width:
+  5
+type:
+  d = Convert argument as a decimal number.
diff --git a/w1e2_a1.rb b/w1e2_a1.rb
@@ -0,0 +1 @@
+puts "%05d" % 123 # => Prints 00123
diff --git a/w1e3.md b/w1e3.md
@@ -0,0 +1,9 @@
+Exercise3. Write a Ruby program that displays how old I am, in years, if I am 
+979000000 seconds old. 
+
+Display the result as a floating point (decimal) number to two decimal places (
+for example, 17.23).
+
+Note: To format the output to say 2 decimal places, we can use the Kernel's 
+format method. For example, if x = 45.5678 then format("%.2f", x) will return 
+the string 45.57
diff --git a/w1e3_a1.rb b/w1e3_a1.rb
@@ -0,0 +1,6 @@
+def how_old(age_in_seconds)
+  Float(age_in_seconds) / 60 / 60 / 24 / 365
+end
+
+age_in_seconds = 979_000_000
+puts "You are %.2f years old" % how_old(age_in_seconds)
diff --git a/w1e4.md b/w1e4.md
@@ -0,0 +1,2 @@
+Exercise4. Write a Ruby program that tells you how many minutes there are in a 
+year (do not bother right now about leap years etc.).
diff --git a/w1e4_a1.rb b/w1e4_a1.rb
@@ -0,0 +1,4 @@
+# Almost a sarcastic answer.  But in reality, the simplest thing that solves
+# the problem is the best solution, generally, so this is an awesome start.
+
+puts 525600
diff --git a/w1e4_a2.rb b/w1e4_a2.rb
@@ -0,0 +1,7 @@
+minutes = 60 * 24 * 365
+
+puts "There are #{minutes} minutes in a year."
+
+
+# =>  "There are 525600 minutes in a year"
+
diff --git a/w1e5.md b/w1e5.md
@@ -0,0 +1,9 @@
+Exercise 5. The following program prints the value of the variable. Why?
+
+```ruby
+my_string = 'Hello Ruby World'
+def my_string
+  'Hello World'
+end
+puts my_string
+```
diff --git a/w1e5_a1.md b/w1e5_a1.md
@@ -0,0 +1,7 @@
+The puts command is pointing to the variable 'my_string', where the output is 
+'Hello Ruby World'. The method 'my_string' is never called.
+
+The method can be called in several ways.  The simplest is my_string() with the 
+parenthesis making it clear that it is a method call.
+
+Generally, you would carefully consider the wisdom of using the same name for a variable as a method in the same scope.
diff --git a/w1e6.md b/w1e6.md
@@ -0,0 +1,11 @@
+Exercise6. Write a method called convert that takes one argument which is a 
+temperature in degrees Fahrenheit. 
+
+This method should return the temperature in degrees Celsius. 
+
+To format the output to say 2 decimal places, we can use the Kernel's format method.
+
+For example, if x = 45.5678 then format("%.2f", x) will return the string "45.57".
+This is also to say that if x = 10 then format("$.2f", x) will return the string "10.00"
+
+Another way is to use the round function as follows: puts (x*100).round/100.0
diff --git a/w1e6_a1.rb b/w1e6_a1.rb
@@ -0,0 +1,6 @@
+
+def convert(temperature_in_F)
+  (temperature_in_F - 32) / 1.8
+end
+
+puts "%.2f" % convert(-40) # => -40.00
diff --git a/README.md b/README.md
@@ -0,0 +1 @@
+A collection of exercises and answers.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Exercise4. Write a Ruby program that tells you how many minutes there are in a
		year (do not bother right now about leap years etc.).