Problem 1. Write a function copy_rev(s)
that takes a string s
and returns a new string that consists of an original string s
followed by its reverse copy.
For example, copy_rev("aBcd")
should return "aBcddcBa"
.
Problem 2. Write functions
copy_to_len_whole(s, l)
that returns the maximum length string made of copies of s
(only the whole s
, no slicing) with the length at most l
,copy_to_len_sliced(s, l)
that returns the maximum length string made of copies of s
with the length exactly l
; if the length of s
doesn't match, it ends with the beginning slice of s
.For example,
copy_to_len_whole("12345", 17)
should return "123451234512345"
(length 15);copy_to_len_sliced("12345", 17)
should return "12345123451234512"
(length 17).You may assume that s
is not an empty string and that l >= 0
.
Problem 3. Write functions
fade_copies_left(s)
that returns the string made by concatenating s
with its left slices of decreasing sizes, i.e., with the s
without the last character, then with s
without the last two characters, etc;fade_copies_right(s)
that returns the string made by concatenating s
with its right slices of decreasing sizes, i.e., with the s
without the first character, then with s
without the first two characters, etc.For example,
fade_copies_left("abcde")
should return "abcdeabcdabcaba"
;fade_copies_right("abcde")
should return "abcdebcdecdedee"
.Problem 4. We define words as sequences of non-space characters separated by a single space.
Write a function last_word(s)
that returns the last word in s
, i.e., the substring beginning after the last occurence of the space character " "
in s
all the way to the end. If the string s
ends with a space, the function returns an empty string ""
. If the string contains no spaces, the whole string is its last word.
Further, write a program that loads an integer n
and then n
strings which it prints sorted by the last word.
Problem 5. We define words as sequences of non-space characters separated by a sequence of consecutive spaces (one or more of them).
Write a function second_word(s)
that returns the second word in s
. Words are mutually separated by one or more spaces. You may assume that s
will not start with a space.
For example, in the string "This is a sentence."
the second word is "is" even though there are 5 spaces before it.