Reverse words in a string

Reverse words in a string is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

The task is to reverse the order of all tokens in a number of strings.

• Hey you, Bub!   would be shown reversed as:   Bub! you, Hey

• Tokens   are any non-blank characters separated by blanks.

• You can consider the ten strings as ten lines, and tokens as words.

• Multiple (or superfluous blanks) can be compressed into one blank.

• Some strings have no words, so a blank string (line) should be shown.

• Display the strings in order (1^st, 2^nd, 3^rd, ···), and one string per line.

• Keep the letter case (upper/lower) and all punctuation intact.

• This example hasn't any tabs or other non-visible characters.

             (ten lines within the box)
 line
     ╔════════════════════════════════════════╗
   1 ║  ---------- Ice and Fire ------------  ║
   2 ║                                        ║  ◄─── a blank line here.
   3 ║  fire, in end will world the say Some  ║
   4 ║  ice. in say Some                      ║
   5 ║  desire of tasted I've what From       ║
   6 ║  fire. favor who those with hold I     ║
   7 ║                                        ║  ◄─── a blank line here.
   8 ║  ... elided paragraph last ...         ║
   9 ║                                        ║  ◄─── a blank line here.
  10 ║  Frost Robert -----------------------  ║
     ╚════════════════════════════════════════╝

C

<lang c>#include <stdio.h>

1. include <ctype.h>

void rev_print(char *s, int n) {

       for (; *s && isspace(*s); s++);
       if (*s) {
               char *e;
               for (e = s; *e && !isspace(*e); e++);
               rev_print(e, 0);
               printf("%.*s%s", (int)(e - s), s, " " + n);
       }
       if (n) putchar('\n');

}

int main(void) {

       char *s[] = {
               "---------- Ice and Fire ------------",
               "                                    ",
               "fire, in end will world the say Some",
               "ice. in say Some                    ",
               "desire of tasted I've what From     ",
               "fire. favor who those with hold I   ",
               "                                    ",
               "... elided paragraph last ...       ",
               "                                    ",
               "Frost Robert -----------------------",
               0
       };
       int i;
       for (i = 0; s[i]; i++) rev_print(s[i], 1);

       return 0;

}</lang> Output is the same as everyone else's.

D

<lang d>void main() {

   import std.stdio, std.string, std.range;

   immutable text =

"---------- Ice and Fire ------------

fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I

... elided paragraph last ...

Frost Robert -----------------------";

   writefln("%(%-(%s %)\n%)",
            text.splitLines.map!(r => r.split.retro));

}</lang> The output is the same as the Python entry.

J

Treated interactively:

<lang J> ([:;@|.[:<;.1 ' ',]);._2]0 :0

---

Ice and Fire ------------

 fire, in end will world the say Some
 ice. in say Some
 desire of tasted I've what From
 fire. favor who those with hold I

  ... elided paragraph last ...

 Frost Robert -----------------------

)

------------ Fire and Ice ----------  
                                      
Some say the world will end in fire,  
Some say in ice.                      
From what I've tasted of desire       
I hold with those who favor fire.     
                                      
... last paragraph elided ...         
                                      
----------------------- Robert Frost  

</lang>

Perl 6

<lang>say .words.reverse for q:to/END/.lines;

---

Ice and Fire ------------

fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I

... elided paragraph last ...

Frost Robert ----------------------- END </lang>

Output:

------------ Fire and Ice ----------

Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.

... last paragraph elided ...

----------------------- Robert Frost

Python

<lang python>>>> text = \

---

Ice and Fire ------------

fire, in end will world the say Some ice. in say Some desire of tasted I've what From fire. favor who those with hold I

... elided paragraph last ...

Frost Robert ----------------------- >>> for line in text.split('\n'): print(' '.join(line.split()[::-1]))

---

Fire and Ice ----------

Some say the world will end in fire, Some say in ice. From what I've tasted of desire I hold with those who favor fire.

... last paragraph elided ...

---

Robert Frost

>>> </lang>

REXX

<lang rexx>/*REXX pgm reverses the order of tokens in a string, but not the letters*/ @. = @.1 = "---------- Ice and Fire ------------" @.2 = ' ' @.3 = "fire, in end will world the say Some" @.4 = "ice. in say Some" @.5 = "desire of tasted I've what From" @.6 = "fire. favor who those with hold I" @.7 = ' ' @.8 = "... elided paragraph last ..." @.9 = ' ' @.10 = "Frost Robert -----------------------"

 do   j=1  while  @.j\==;  $=       /*process each "line"; nullify $.*/
   do k=1  for  words(@.j)            /*process each word in the string*/
   $=word(@.j,k) $                    /*prepend the word to a new line.*/
   end   /*k*/                        /* [↑]  could do this another way*/
 say $                                /*display newly constructed line.*/
 end     /*j*/                        /*stick a fork in it, we're done.*/</lang>

output when using the ten lines of input:

------------ Fire and Ice ----------

Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.

... last paragraph elided ...

----------------------- Robert Frost