Exercises from Chapter 12
One Billion Seconds!
Well, I don’t know your brithday, so I don’t know how
you’d do it, but here’s how I would do it:
|
puts(Time.gm(1976, 8, 3, 13, 31) + 10**9) |
|
|
|
Happy Birthday!
How you could do it:
puts 'What year were you born?' |
b_year = gets.chomp.to_i |
|
puts 'What month were you born? (1-12)' |
b_month = gets.chomp.to_i |
|
puts 'What day of the month were you born?' |
b_day = gets.chomp.to_i |
|
b = Time.local(b_year, b_month, b_day) |
t = Time.new |
|
age = 1 |
|
while Time.local(b_year + age, b_month, b_day) <= t |
puts 'SPANK!' |
age = age + 1 |
end |
| <= | What year were you born? |
| => | 2009 |
| <= | What month were you born? (1-12) |
| => | 2 |
| <= | What day of the month were you born? |
| => | 2nd |
| <= | SPANK! |
| | SPANK! |
| | SPANK! |
| | SPANK! |
How I would do it:
puts 'Hey, when were you born? (Please use YYYYMMDD format.)' |
input = gets.chomp |
|
b_year = input[0..3].to_i |
b_month = input[4..5].to_i |
b_day = input[6..7].to_i |
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t = Time.new |
|
t_year = t.year |
t_month = t.month |
t_day = t.day |
|
age = t_year - b_year |
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if t_month < b_month || (t_month == b_month && t_day < b_day) |
age -= 1 |
end |
|
if t_month == b_month && t_day == b_day |
puts 'HAPPY BIRTHDAY!!' |
end |
|
age.times { puts 'SPANK!' } |
| <= | Hey, when were you born? (Please use YYYYMMDD format.) |
| => | 20090202 |
| <= | SPANK! |
| | SPANK! |
| | SPANK! |
| | SPANK! |
Party Like It’s
roman_to_integer mcmxcix!
How you could do it:
def roman_to_integer roman |
digit_vals = {'i' => 1, |
'v' => 5, |
'x' => 10, |
'l' => 50, |
'c' => 100, |
'd' => 500, |
'm' => 1000} |
total = 0 |
prev = 0 |
index = roman.length - 1 |
while index >= 0 |
c = roman[index].downcase |
index = index - 1 |
val = digit_vals[c] |
if !val |
puts 'This is not a valid roman numeral!' |
return |
end |
|
if val < prev |
val = val * -1 |
else |
prev = val |
end |
total = total + val |
end |
|
total |
end |
|
puts(roman_to_integer('mcmxcix')) |
puts(roman_to_integer('CCCLXV')) |
How I would do it:
def roman_to_integer roman |
digit_vals = {'i' => 1, |
'v' => 5, |
'x' => 10, |
'l' => 50, |
'c' => 100, |
'd' => 500, |
'm' => 1000} |
total = 0 |
prev = 0 |
roman.reverse.each_char do |c_or_C| |
c = c_or_C.downcase |
val = digit_vals[c] |
if !val |
puts 'This is not a valid roman numeral!' |
return |
end |
if val < prev |
val *= -1 |
else |
prev = val |
end |
total += val |
end |
|
total |
end |
|
puts(roman_to_integer('mcmxcix')) |
puts(roman_to_integer('CCCLXV')) |
Birthday Helper!
How you could do it:
|
birth_dates = {} |
File.read('birthdates.txt').each_line do |line| |
line = line.chomp |
|
|
first_comma = 0 |
while line[first_comma] != ',' && |
first_comma < line.length |
first_comma = first_comma + 1 |
end |
|
name = line[0..(first_comma - 1)] |
date = line[-12..-1] |
|
birth_dates[name] = date |
end |
|
|
puts 'Whose birthday would you like to know?' |
name = gets.chomp |
date = birth_dates[name] |
|
if date == nil |
puts "Oooh, I don't know that one..." |
else |
puts date[0..5] |
end |
| <= | Whose birthday would you like to know? |
| => | Christopher Plummer |
| <= | Dec 13 |
How I would do it:
|
birth_dates = {} |
|
File.readlines('birthdates.txt').each do |line| |
name, date, year = line.split(',') |
birth_dates[name] = Time.gm(year, *(date.split)) |
end |
|
|
puts 'Whose birthday would you like to know?' |
name = gets.chomp |
bday = birth_dates[name] |
|
if bday == nil |
puts "Oooh, I don't know that one..." |
else |
now = Time.new |
age = now.year - bday.year |
|
if now.month > bday.month || (now.month == bday.month && now.day > bday.day) |
age += 1 |
end |
|
if now.month == bday.month && now.day == bday.day |
puts "#{name} turns #{age} TODAY!!" |
else |
date = bday.strftime "%b %d" |
puts "#{name} will be #{age} on #{date}." |
end |
end |
| <= | Whose birthday would you like to know? |
| => | Christopher Pine |
| <= | Christopher Pine will be 37 on Aug 03. |
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