Pointers, pointers, pointers!

Question

Introduction

In the error outputs of some languages such as Java, a pointer is shown to give the programmer an idea of exactly where the error went wrong.

Take this example on Ideone:

Main.java:12: error: ';' expected
    Invalid Java!
                ^

Notice the caret shows where the invalid code is?

Challenge

Your challenge is: given number N and string S, place a pointer on the Nth character in S.

Examples

Input: 2, "Lorem ipsum, dollar sit amet."

Output:

Lorem ipsum, dollar sit amet.
 ^

Rules

• Input is received via STDIN or function parameters
• Output is printed out to the console or returned
• Trailing new lines, spaces etc are allowed in the output
• The pointer character must be a ^ caret and must be on a new line.
• This is code golf, so the shortest answer wins. Good luck!

Answer 1

Integral, 7 6 Bytes

▼8gv^►

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-1 thanks to @petStorm

Answer 2

Python 3, 29 bytes 31

lambda N,S:S+'\n'+' '*~-N+'^'

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A Plain Comprehensible snippet, used function lambda function and concatenation

Answer 3

Hexagony, 37 bytes (Side Length 4)

?},$;}<..0~\>(</,<}.>/>;/@\'$'65;\94\

    ? } , $
   ; } < . .
  0 ~ \ > ( <
 / , < } . > /
  > ; / @ \ '
   $ ' 6 5 ;
    \ 9 4 \

Input is of the form: "[number] [string]" ex: 3 Hello World! would output:

Hello World!
  ^

In terms of pictures, I've split it up into: Most of the program, and the End

Red: ?},$

  `?}` gets the pointer num and moves the MP
  `,` skips the space
  `$` creates a jump to the for loop

Red / Orange ,<;

  `,` gets the next byte from stdin
  `<` goes out of loop if byte is <= 0
  `;` prints the byte

Green ~0;56'$

  `~0` when Hexagony reads an empty byte, it puts a -1 in memory, 
       I then flip that to 1 and append a 0 to get 10
       This saves 1 char over `*10` which I needed to save
  `;` prints the newline
  `56` appends a 56 to the 10 to get 1056
       taken modulo 256, it comes out to 32 which is ascii
       for space; this also saves 1 char over `*32`
  `'` moves the MP back to the pointer num
  `$` jumps into the space printing loop

Green / Blue (<};'

  `(` decrements by 1 before checking if 0 so that it
      prints pointer val - 1 spaces
  `<` loops if counter > 0
  `};'` moves to the memory value containing the space,
        prints it, then moves back

Purple }'94

  `}'` the `'` was already in the path, so I used } to move it forward
       so it would move back
  `94` puts ascii `^` into memory

Starting from where purple left off, I was lucky that the program basically worked itself out. It ends up not changing the 94 in memory until it prints it, and then eventually makes its way to a blank space that hadn't been used and so I put the stopping point there and it all worked out. Fun challenge!

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Answer 4

APL (Dyalog Unicode), 23 bytes

⊣,(⎕UCS 10),'^',⍨' '⍴⍨⊢

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Explanation:

⊣,(⎕UCS 10),'^',⍨' '⍴⍨⊢
⊣,(⎕UCS 10)              ⍝ original line + linefeed
            '^',⍨' '⍴⍨⊢  ⍝ generate the pointer

Explaining the generator by example:
               ('^',⍨' '⍴⍨⊢)
               {'^',⍨' '⍴⍨⍵}
               {(' '⍴⍨⍵),'^'}
               {(⍵⍴' '),'^'}
                (⍵⍴' ')          ⍝ generate ⍵ spaces
                        '^'      ⍝ append the pointer

Answer 5

SpecBAS - 34

1 INPUT n,s$: PRINT s$'TAB n-1;"^"

Apostrophe in PRINT forces a new line, then just have to move the cursor to correct position.

Answer 6

GolfScript 11

n@~(' '*'^'

Test here.

Answer 7

JavaScript - 52 bytes

Here's mine, it's pretty simple.

function f(n,s){return s+"\n"+Array(n).join(" ")+"^"}

Usage:

$ console.log(f(7, "Any string at all"))

Any string at all
      ^

It points at the seventh character.

Answer 8

Perl 5, 31

sub{"$_[0]
"." "x($_[1]-1)."^"}

Answer 9

Perl, 45

This is a pretty horribly golfed answer, but it's my first attempt at code golf.

<>=~/(.*), "(.*)"/;print"$2
"." "x($1-1)."^";

Answer 10

F#, 31 characters

let p n s=s+"\n"+"^".PadLeft(n)

Answer 11

Ruby, 17 23 22

->s,n{s+$/+?\s*~-n+?^}

This is as short as I can go from something like this:

# Lambdas are like Procs, except with a fixed num of arguments
lambda do |sourceLine, offset|
    # The last expression is returned as the lambda's return value.
    # Multiplying a string by N will repeat it N times.
    sourceLine + "\n" + " " * (offset - 1) + "^"
end

Answer 12

Perl, 20

After seeing @Digital Trauma's answer, I wanted to port his answer to Perl to show an another example of accepting the input numbers as unary as a default. This is based on the meta discussion.

$i++&y/1/ /&s/ $/^/

19 characters +1 for -p flag.

Run with:

{ echo "Lorem ipsum, dollar sit amet."; echo 111; } | perl -pe'$i++?y/1/ /&&s/ $/^/:1'

Answer 13

C, 60 49

f(n,s){puts(s);while(n-=1)putch(' ');putch('^');}

First post, so I guess it's not that good.

Answer 14

Scala (49 42 bytes)

def p(i:Int,s:String)=s+"\n"+" "*(i-1)+"^"

---

scala> def p(i:Int,s:String)=s+"\n"+" "*(i-1)+"^"
p: (i: Int, s: String)String

scala> p(2, "Lorem ipsum, dollar sit amet.")
res0: String =
Lorem ipsum, dollar sit amet.
 ^

Answer 15

J, 19

Including parentheses!

The verb:

(],:'^',~' '#~<:@[)

Use:

9 (],:'^',~' '#~<:@[) 'Invalid Java!'
Invalid Java!
        ^

Answer 16

This is my first code golf, but here I go.

Haskell, 36

f s n=s++'\n':replicate(n-1)' '++"^"

The regular version being

placeCaret :: String -> Integer -> String
placeCaret s n = s ++ '\n' : replicate (n - 1) ' ' ++ "^"

So, not really much change. Clearly, the replicate is wasting the most space here, but as far as I know there are no alternatives in Prelude. I played a bit with other things which could have been cool tricks, but they all ended up being the same length.

Example usage:

Prelude> putStrLn $ f ['a'..'z'] 7
abcdefghijklmnopqrstuvwxyz
      ^

putStrLn is needed so that the newline will be displayed as a newline instead of "\n" (in GHCi only).

I know I'm VERY late to this party, but whatever.

Answer 17

Straw, 13 bytes

<#<>
> ,}*>^>

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^ is the only non-alphanumeric character (with \) to not be assigned to a command, so no need for a string literal to push it.

Answer 18

Haskell, 30 bytes

s!n=s++'\n':([1..n]>>" ")++"^"

Answer 19

C++ (with the standard library) - 159 121 bytes (-38 by Riley)

#include<iostream>
using namespace std;int main(int c,char**v){cout<<string(v[2])<<endl<<string(stoi(v[1])-1,' ')<<"^";}

Gets input from the command line args.
Example usage: ./a.out 8 "hello, world"

This is my first ever code golf, so if you have any tips, that would be great!

Answer 20

Vim 9 bytes

jD@"a <esc>r^

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Note that <esc> is a single byte, namely 0x1B, but since that byte is unprintable, I added a flag and used <esc> instead. This version uses the unprintable.

Explanation:

j               " Move down one line
 D              " Delete everything on this line, and save it in the unnamed register
  @"            " 'n' times
    a <esc>     " Append a 'space'
           r^   " Replace this last space with caret

Answer 21

Common Lisp, 40 35

(format t"~A
~VT^"(read)(1-(read)))

-5 bytes thanks to PrzemysławP.

Answer 22

Underload, 23 bytes

(S(
)S()(( )S^)!!^(^)S)

Assumes S is a string on the stack. N should be given in unary. It should be a sequence of : in between the ) and ! on the second line. For example:

(S(
)S()(( )S^)::::!!^(^)S)

The :::: represents N=4.

Answer 23

Perl 5 -n, 20 bytes

say<>;say$"x--$_,'^'

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Unlike a previous answer of the same byte count, this does not require the input to be in unary.

Answer 24

Momema, 50 bytes

1+*-8-1s00*-9-9*0s=+1*0-9 10c01+*1-1-9 32c=*1-9 94

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Explanation

1   +*-8-1  #  mem[1] = mem[-8] + (-1)   #  a = getnum() - 1
s   0       #  do {                      #  do {
0   *-9     #    mem[0] = mem[-9]        #    b = getchar()
-9  *0      #    mem[-9] = mem[0]        #    putchar(b)
s   =+1*0   #  } while (mem[0] + 1)      #  } while (b != -1)
-9  10      #  mem[-9] = 10              #  putchar('\n')
c   0       #  do {                      #  do {
1   +*1-1   #    mem[1] = mem[1] + (-1)  #    a = a - 1
-9  32      #    mem[-9] = 32            #    putchar(32)
c   =*1     #  } while (mem[1])          #  } while (b != 0)
-9  94      #  mem[-9] = 94              #  putchar(94)

Memory addresses -8 and -9 are memory-mapped for numeric and character IO respectively.

Answer 25

Keg, 9 bytes

᠀
¿; ℠*\^

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Answer 26

Rust, 32 bytes

|n,s|print!("{}
{:>2$}",s,"^",n)

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Answer 27

Brain-Flak -A, 116 bytes

([{}]()<{({}<>)<>}(((((()()()()()){}()){}()){}()){})>){((){}<((((()()()()){}){}){})>)}{}((()()()()()){}){<>({}<>)}{}

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Answer 28

05AB1E, 7 bytes

'^I<ú‚»

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Explantion

'^       # push caret
  I<ú    # prepend with input-1 spaces
     ‚   # pair with second input
      »  # join by newline

Answer 29

J, 9 bytes

,:'^'{.~-

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        -   negate the number
  '^'{.~    take that many characters from the string "^"
,:          append 2 items

Answer 30

Zsh -F, 20 bytes

printf %s\\n%*c $@ ^

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Method stolen from the C answer.