View Subcategory
Reverse the characters in a string
Given the string
"reverse me", produce the string "em esrever"
ruby
puts "reverse me".reverse
erlang
Reversed = lists:reverse("reverse me"),
Reversed = revchars("reverse me"),
csharp
var str = "reverse me";
Console.WriteLine(new String(str.Reverse().ToArray()));
Console.WriteLine(new String(str.Reverse().ToArray()));
cpp
String^ s = "reverse me";
array<Char>^ sa = s->ToCharArray();
Array::Reverse(sa);
String^ sr = gcnew String(sa);
array<Char>^ sa = s->ToCharArray();
Array::Reverse(sa);
String^ sr = gcnew String(sa);
std::string s = "reverse me";
std::reverse(s.begin(), s.end());
std::reverse(s.begin(), s.end());
std::string s = "reverse me";
std::string sr(s.rbegin(), s.rend());
std::string sr(s.rbegin(), s.rend());
std::string s = "reverse me";
std::swap_ranges(s.begin(), (s.begin() + s.size() / 2), s.rbegin());
std::swap_ranges(s.begin(), (s.begin() + s.size() / 2), s.rbegin());
clojure
(require '[clojure.contrib.str-utils2 :as str])
(str/reverse "reverse me")
(str/reverse "reverse me")
(apply str (reverse "reverse me"))
go
package main;
import "utf8";
import "fmt";
func reverse(s string) string {
o := make([]int, utf8.RuneCountInString(s))
i := len(o)
for _, c := range s {
i--
o[i] = c
}
return string(o)
}
func main() {
fmt.Print(reverse("reverse me"));
}
import "utf8";
import "fmt";
func reverse(s string) string {
o := make([]int, utf8.RuneCountInString(s))
i := len(o)
for _, c := range s {
i--
o[i] = c
}
return string(o)
}
func main() {
fmt.Print(reverse("reverse me"));
}
func Reverse(s string) string {
runes := []rune(s)
for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
runes[i], runes[j] = runes[j], runes[i]
}
return string(runes)
}
runes := []rune(s)
for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
runes[i], runes[j] = runes[j], runes[i]
}
return string(runes)
}
Reverse the words in a string
Given the string
"This is a end, my only friend!", produce the string "friend! only my end, the is This"
ruby
reversed = text.split.reverse.join(' ')
erlang
Reversed = string:join(lists:reverse(string:tokens("This is the end, my only friend!", " ")), " "),
csharp
var str = "This is a end, my only friend!";
str = String.Join(" ", str.Split().Reverse().ToArray());
Console.WriteLine(str);
str = String.Join(" ", str.Split().Reverse().ToArray());
Console.WriteLine(str);
cpp
array<Char>^ sep = {L' '};
array<String^>^ words =
String(L"This is the end, my only friend!").Split(sep, StringSplitOptions::RemoveEmptyEntries);
Array::Reverse(words); String^ newwords = String::Join(L" ", words);
array<String^>^ words =
String(L"This is the end, my only friend!").Split(sep, StringSplitOptions::RemoveEmptyEntries);
Array::Reverse(words); String^ newwords = String::Join(L" ", words);
std::string words = "This is the end, my only friend!"; std::vector<std::string> swv;
boost::split(swv, words, boost::is_any_of(" ")); std::reverse(swv.begin(), swv.end());
std::string newwords = (std::for_each(swv.begin(), swv.end(), StringTAndJ())).value();
boost::split(swv, words, boost::is_any_of(" ")); std::reverse(swv.begin(), swv.end());
std::string newwords = (std::for_each(swv.begin(), swv.end(), StringTAndJ())).value();
clojure
(require '[clojure.contrib.str-utils2 :as str])
(str/join " " (reverse (str/split "this is the end, my only friend!" #" ")))
(str/join " " (reverse (str/split "this is the end, my only friend!" #" ")))
(apply str (interpose " " (reverse (re-seq #"[^\s]+" "This is the end, my only friend!"))))
go
words := strings.Split("This is the end, my only friend!", " ")
nr := len(words)
reversed := make([]string, nr)
for i, word := range words {
reversed[nr - i - 1] = word
}
s := strings.Join(reversed, " ")
fmt.Println(s)
nr := len(words)
reversed := make([]string, nr)
for i, word := range words {
reversed[nr - i - 1] = word
}
s := strings.Join(reversed, " ")
fmt.Println(s)
func reverse(list []string) ([]string) {
if len(list) == 1 {
return list
}
return append(reverse(list[1:]), list[0])
}
func main() {
words := strings.Split("This is the end, my only friend!", " ")
s := strings.Join(reverse(words), " ")
fmt.Println(s)
}
if len(list) == 1 {
return list
}
return append(reverse(list[1:]), list[0])
}
func main() {
words := strings.Split("This is the end, my only friend!", " ")
s := strings.Join(reverse(words), " ")
fmt.Println(s)
}
Text wrapping
Wrap the string
> The quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog.
"The quick brown fox jumps over the lazy dog. " repeated ten times to a max width of 78 chars, starting each line with "> ", yielding this result:
> The quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog.
ruby
prefix = "> "
string = "The quick brown fox jumps over the lazy dog. " * 10
width = 78
realwidth = width - prefix.length
print string.gsub(/(.{1,#{realwidth}})(?: +|$)\n?|(.{#{realwidth}})/, "#{prefix}\\1\\2\n")
string = "The quick brown fox jumps over the lazy dog. " * 10
width = 78
realwidth = width - prefix.length
print string.gsub(/(.{1,#{realwidth}})(?: +|$)\n?|(.{#{realwidth}})/, "#{prefix}\\1\\2\n")
erlang
TextWrap = textwrap(string:copies(Input, 10), 73 - length(Prefix)),
lists:foreach(fun (Line) -> io:format("~s~n", [string:concat(Prefix, Line)]) end, string:tokens(TextWrap, "\n")).
lists:foreach(fun (Line) -> io:format("~s~n", [string:concat(Prefix, Line)]) end, string:tokens(TextWrap, "\n")).
csharp
using System;
using System.Text;
using System.Linq; // used for Array.ToList() extension
public class TextWrapper {
/// <summary>
/// Wrap the given text to a given width.
/// </summary>
/// <param name="text">The text to be wrapped</param>
/// <param name="width">The maximum width of each line</param>
/// <param name="prefix">Begin each line with this prefix</param>
/// <returns>The wrapped text</returns>
public string Wrap(string text, int width, string prefix) {
var words = text.Split(' ').ToList();
var result = new StringBuilder(prefix);
width = width - prefix.Length;
prefix = "\n" + prefix;
int lineSize = 0;
foreach (var word in words) {
int wordLen = word.Length;
// Do we need to start a new line?
if ((lineSize + wordLen) > width) {
result.Remove(result.Length - 1, 1); // remove trailing space
lineSize = 0;
result.Append( prefix );
}
result.Append(word).Append(' ');
lineSize += wordLen + 1;
}
return result.ToString();
}
public static void Main() {
var prefix = "> ";
var sentence = "The quick brown fox jumps over the lazy dog. ";
var text = "";
for (int i = 0; i < 10; i++)
text += sentence;
// The description said lines of length 78, but
// the example was 72...
Console.WriteLine(new TextWrapper().Wrap(text, 72, prefix));
}
}
using System.Text;
using System.Linq; // used for Array.ToList() extension
public class TextWrapper {
/// <summary>
/// Wrap the given text to a given width.
/// </summary>
/// <param name="text">The text to be wrapped</param>
/// <param name="width">The maximum width of each line</param>
/// <param name="prefix">Begin each line with this prefix</param>
/// <returns>The wrapped text</returns>
public string Wrap(string text, int width, string prefix) {
var words = text.Split(' ').ToList();
var result = new StringBuilder(prefix);
width = width - prefix.Length;
prefix = "\n" + prefix;
int lineSize = 0;
foreach (var word in words) {
int wordLen = word.Length;
// Do we need to start a new line?
if ((lineSize + wordLen) > width) {
result.Remove(result.Length - 1, 1); // remove trailing space
lineSize = 0;
result.Append( prefix );
}
result.Append(word).Append(' ');
lineSize += wordLen + 1;
}
return result.ToString();
}
public static void Main() {
var prefix = "> ";
var sentence = "The quick brown fox jumps over the lazy dog. ";
var text = "";
for (int i = 0; i < 10; i++)
text += sentence;
// The description said lines of length 78, but
// the example was 72...
Console.WriteLine(new TextWrapper().Wrap(text, 72, prefix));
}
}
cpp
String^ input = ::copies("The quick brown fox jumps over the lazy dog. ", 10);
String^ sep = " "; String^ prefix = "> ";
String^ wrapped = textwrap(input, 74 - prefix->Length, sep, prefix);
Console::WriteLine("{0}", wrapped);
String^ sep = " "; String^ prefix = "> ";
String^ wrapped = textwrap(input, 74 - prefix->Length, sep, prefix);
Console::WriteLine("{0}", wrapped);
void rep(ostream &os, const string& str, int times)
{
while (times--)
os << str;
}
void wrap(ostream &os, const string& str, const string &prefix, int width)
{
int line_len = width;
bool first_word = true;
width -= prefix.size();
BOOST_FOREACH(string word, tokenizer<char_separator<char>>(str, char_separator<char>(" ")))
{
line_len += word.size();
if (line_len++ < width)
os << ' ';
else {
if (first_word)
first_word = false;
else
os << endl;
os << prefix;
line_len = word.size();
}
os << word;
}
os << endl;
}
int main()
{
stringstream input;
rep(input, "The quick brown fox jumps over the lazy dog. ", 10);
wrap(cout, input.str(), "> ", 72);
}
{
while (times--)
os << str;
}
void wrap(ostream &os, const string& str, const string &prefix, int width)
{
int line_len = width;
bool first_word = true;
width -= prefix.size();
BOOST_FOREACH(string word, tokenizer<char_separator<char>>(str, char_separator<char>(" ")))
{
line_len += word.size();
if (line_len++ < width)
os << ' ';
else {
if (first_word)
first_word = false;
else
os << endl;
os << prefix;
line_len = word.size();
}
os << word;
}
os << endl;
}
int main()
{
stringstream input;
rep(input, "The quick brown fox jumps over the lazy dog. ", 10);
wrap(cout, input.str(), "> ", 72);
}
clojure
(doseq [line (re-seq #".{0,70} "
(apply str
(repeat 10 "The quick brown fox jumps over the lazy dog. ")))]
(println ">" line))
(apply str
(repeat 10 "The quick brown fox jumps over the lazy dog. ")))]
(println ">" line))
go
import "fmt"
import "strings"
const WIDTH = 72
func main() {
s := "The quick brown fox jumps over the lazy dog."
words := strings.Split(s, " ")
tmp := words
for i, pos := 0, 0; i < 10; i++ {
for len(words) > 0 {
if pos == 0 {
fmt.Printf("> ")
}
if pos + len(words[0]) > WIDTH {
fmt.Printf("\n")
pos = 0
} else {
fmt.Printf("%s ", words[0])
pos += len(words[0]) + 1
words = words[1:]
}
}
words = tmp
}
fmt.Printf("\n")
}
import "strings"
const WIDTH = 72
func main() {
s := "The quick brown fox jumps over the lazy dog."
words := strings.Split(s, " ")
tmp := words
for i, pos := 0, 0; i < 10; i++ {
for len(words) > 0 {
if pos == 0 {
fmt.Printf("> ")
}
if pos + len(words[0]) > WIDTH {
fmt.Printf("\n")
pos = 0
} else {
fmt.Printf("%s ", words[0])
pos += len(words[0]) + 1
words = words[1:]
}
}
words = tmp
}
fmt.Printf("\n")
}
Remove leading and trailing whitespace from a string
Given the string
" hello " return the string "hello".
ruby
puts " hello ".strip
" hello ".strip!
erlang
Trimmed = string:strip(S),
csharp
string str = " hello ";
str = str.Trim();
Console.WriteLine(str);
str = str.Trim();
Console.WriteLine(str);
cpp
String^ s = " hello "; String^ trimmed = s->Trim();
clojure
(use 'clojure.contrib.str-utils2)
(trim " hello ")
(trim " hello ")
(clojure.string/trim " hello ")
(.trim " hello ")
go
s := strings.TrimSpace(" hello ")
Simple substitution cipher
Take a string and return the ROT13 and ROT47 (Check Wikipedia) version of the string.
For example:
String is: Hello World #123
ROT13 returns: Uryyb Jbeyq #123
ROT47 returns: w6==@ (@C=5 R`ab
For example:
String is: Hello World #123
ROT13 returns: Uryyb Jbeyq #123
ROT47 returns: w6==@ (@C=5 R`ab
ruby
rot13 = "Hello World #123".tr!("A-Za-z", "N-ZA-Mn-za-m")
rot47 = "Hello World #123".tr!("\x21-\x7e", "\x50-\x7e\x21-\x4f")
rot47 = "Hello World #123".tr!("\x21-\x7e", "\x50-\x7e\x21-\x4f")
erlang
rot13(Str) ->
lists:map(fun(A) ->
if
A >= $A, A =< $Z -> ((A - $A + 13) rem 26) + $A;
A >= $a, A =< $z -> ((A - $a + 13) rem 26) + $a;
true -> A
end
end, Str).
rot47(Str) ->
lists:map(fun(A) ->
if
A >= $!, A =< $~ ->
((A - $! + 47) rem 94) + $!;
true -> A
end
end, Str).
lists:map(fun(A) ->
if
A >= $A, A =< $Z -> ((A - $A + 13) rem 26) + $A;
A >= $a, A =< $z -> ((A - $a + 13) rem 26) + $a;
true -> A
end
end, Str).
rot47(Str) ->
lists:map(fun(A) ->
if
A >= $!, A =< $~ ->
((A - $! + 47) rem 94) + $!;
true -> A
end
end, Str).
cpp
#include <algorithm>
#include <iostream>
#include <cctype>
using namespace std;
int rot13(int c) {
if (!isalpha(c)) {
return c;
} else {
char start = islower(c) ? 'a' : 'A';
return ((c - start) + 13) % 26 + start;
}
}
int rot47(int c) {
if (c < 33 || c > 126) {
return c;
} else {
return ((c - 33) + 47) % 94 + 33;
}
}
int main(int argc, char **argv) {
for (int i = 0; i < argc; ++i) {
string original = argv[i];
string rot13enc = original;
transform(original.begin(), original.end(), rot13enc.begin(), rot13);
string rot47enc = original;
transform(original.begin(), original.end(), rot47enc.begin(), rot47);
cout << "original: " << original << endl
<< "rot 13: " << rot13enc << endl
<< "rot 47: " << rot47enc << endl;
}
return 0;
}
#include <iostream>
#include <cctype>
using namespace std;
int rot13(int c) {
if (!isalpha(c)) {
return c;
} else {
char start = islower(c) ? 'a' : 'A';
return ((c - start) + 13) % 26 + start;
}
}
int rot47(int c) {
if (c < 33 || c > 126) {
return c;
} else {
return ((c - 33) + 47) % 94 + 33;
}
}
int main(int argc, char **argv) {
for (int i = 0; i < argc; ++i) {
string original = argv[i];
string rot13enc = original;
transform(original.begin(), original.end(), rot13enc.begin(), rot13);
string rot47enc = original;
transform(original.begin(), original.end(), rot47enc.begin(), rot47);
cout << "original: " << original << endl
<< "rot 13: " << rot13enc << endl
<< "rot 47: " << rot47enc << endl;
}
return 0;
}
clojure
(use 'clojure.contrib.cond)
(defn rot13 [s]
(reduce str
(map #(char (let [c (bit-and (int (char %)) 0xDF)]
(+ % (cond-let [i]
(and (>= c (int \A)) (<= c (int \M))) 13
(and (>= c (int \N)) (<= c (int \Z))) -13
true 0))))
(map #(int (char %)) s))))
(defn rot47 [s]
(reduce str
(map #(char (+ % (cond-let [i]
(and (>= % (int \!)) (<= % (int \O))) 47
(and (>= % (int \P)) (<= % (int \~))) -47
true 0)))
(map #(int (char %)) s))))
(defn rot13 [s]
(reduce str
(map #(char (let [c (bit-and (int (char %)) 0xDF)]
(+ % (cond-let [i]
(and (>= c (int \A)) (<= c (int \M))) 13
(and (>= c (int \N)) (<= c (int \Z))) -13
true 0))))
(map #(int (char %)) s))))
(defn rot47 [s]
(reduce str
(map #(char (+ % (cond-let [i]
(and (>= % (int \!)) (<= % (int \O))) 47
(and (>= % (int \P)) (<= % (int \~))) -47
true 0)))
(map #(int (char %)) s))))
