Suppose the character string is "abc" and user input is 3 then the output becomes "def".
Every character is supposed to be increased by the user input as integer value.
I wrote a code but it is giving an error. Is there any other way to do this?
#!/usr/bin/ruby -w
puts "Enter the value of n";
$n=gets;
s = String.new("abc");
s.split("").each do |i|
$j = 0;
x = i;
begin
x.next;
$j = $j + 1;
end while $j < $n
puts x;
end
There are several things to add in your code:
String.new, you can simply add your string within quotes.str.split("") can be str.chars.$j = $j + 1 can be $j += 1.$j and $n then << should be <.; unless you're writing all in one line.begin; end while can be just while; endI guess it could be like:
n = gets.to_i
s = 'abc'
s.split('').each do |i|
j = 0
x = i
while j < n
x = x.next
j += 1
end
puts x
end
But you could use String#ord over each char in your string to return the ordinal of it, add the user input and then String#chr to get the ASCII character for that number:
# With n being the user's input as integer, in this case 3.
p 'abc'.chars.map { |char| (char.ord + n).chr }.join
# "def"
Added n = gets.to_i as stated in the comments by @Ganesh.
If looking for a Caesar Cipher implementation:
def foo(string, n)
lower = ('a'..'z').to_a.join
upper = ('A'..'Z').to_a.join
string.tr(lower + upper, lower[n..-1] + lower[0...n] + upper[n..-1] + upper[0...n])
end
p foo('XYZ', 1) # "YZA"
p foo('ABC', 1) # "BCD"
p foo('ABC', 3) # "DEF"
Slower, but...
j and n are always numbers, what's the code you're trying with?
You can use tr and rotate. Assumes you want a circular-mapping i.e. 'z' => 'a' for a +1 map.
def caesar str, n
str.tr 'a-z', [*'a'..'z'].rotate(n).join
end
caesar 'abc', 3 #=> 'def'
caesar 'xyz', 3 #=> 'abc'
See docs for info on these methods.
If all characters are lower-case ASCII letters:
def caesar(str, n)
base = 'a'.ord
str.gsub(/./) { |c| (base + (c.ord+n-base) % 26).chr }
end
str = "abcxyza"
caesar(str, 1) #=> "bcdyzab"
caesar(str, 2) #=> "cdezabc"
caesar(str, 25) #=> "zabwxyz"
caesar(str, 26) #=> "abcxyza"
If all characters are ASCII letters:
def caesar(str, n)
str.gsub(/./) do |c|
base = (c==c.upcase ? 'A' : 'a').ord
(base + (c.ord+n-base) % 26).chr
end
end
str = "AbcDefXyZa"
caesar(str, 1) #=> "BcdEfgYzAb"
caesar(str, 2) #=> "CdeFghZaBc"
caesar(str, 25) #=> "ZabCdeWxYz"
caesar(str, 26) #=> "AbcDefXyZa"
<<be<?$n=gets.to_i. See the repl.'xyz'etc?