Increment a numerical string

Increment a numerical string
You are encouraged to solve this task according to the task description, using any language you may know.

This task is about incrementing a numerical string.

ABAP

<lang ABAP>report zz_incstring perform test using: '0', '1', '-1', '10000000', '-10000000'.

form test using iv_string type string.

 data: lv_int  type i,
       lv_string type string.
 lv_int = iv_string + 1.
 lv_string = lv_int.
 concatenate '"' iv_string '" + 1 = "' lv_string '"' into lv_string.
 write / lv_string.

endform. </lang>

Output

"0" + 1 = "1 "
"1" + 1 = "2 "
"-1" + 1 = "0 "
"10000000" + 1 = "10000001 "
"-10000000" + 1 = "9999999-"

ActionScript

<lang ActionScript>function incrementString(str:String):String { return String(Number(str)+1); }</lang>

Ada

The standard Ada package Ada.Strings.Fixed provides a function for trimming blanks from a string. <lang ada>S : String := "12345"; S := Ada.Strings.Fixed.Trim(Source => Integer'Image(Integer'Value(S) + 1), Side => Ada.Strings.Both);</lang>

Aime

<lang aime> o_text(itoa(atoi("2047") + 1)); o_byte('\n'); </lang>

ALGOL 68

Works with: ALGOL 68 version Revision 1 - no extensions to language used

Works with: ALGOL 68G version Any - tested with release 1.18.0-9h.tiny

<lang algol68>STRING s := "12345"; FILE f; INT i; associate(f, s); get(f,i); i+:=1; s:=""; reset(f); put(f,i); print((s, new line))</lang> Output:

+12346

AutoHotkey

<lang autohotkey>str = 12345 MsgBox % str += 1</lang> Output:

12346

AutoIt

<lang autoIt>Global $x = "12345" $x += 1 MsgBox(0,"",$x)</lang> Output:

12346

AWK

The example shows that the string s can be incremented, but after that still is a string of length 2. <lang awk>$ awk 'BEGIN{s="42";s++;print s"("length(s)")"}' 43(2)</lang>

BASIC

Works with: BBC BASIC

Works with: QBasic

Works with: PowerBASIC

Works with: Visual Basic

Works with: Liberty BASIC

<lang qbasic>s$ = "12345" s$ = STR$(VAL(s$) + 1)</lang>

ZX Spectrum Basic

The ZX Spectrum needs line numbers and a let statement, but the same technique can be used:

<lang zxbasic>10 LET s$ = "12345" 20 LET s$ = STR$(VAL(s$) + 1)</lang>

Batch File

Since environment variables have no type distinction all numbers are simply numeric strings:

Works with: Windows NT version 4

<lang dos>set s=12345 set /a s+=1</lang>

Boo

<lang boo>s = "1234" s = (int.Parse(s) + 1).ToString()</lang>

Bracmat

Numbers are strings. Bracmat supports rational numbers, including integers, using arbitrary-precision arithmetic. Pure imaginary numbers are formed using a factor i (or -i). There is no support for floating point arithmetics. (Historically, because the ARM 2 processor in the Archimedes computer didn't sport an FPU.) <lang bracmat>(n=35664871829866234762187538073934873121878/6172839450617283945) &!n+1:?n &out$!n

  35664871829866234762193710913385490405823/6172839450617283945

</lang>

Brat

<lang brat>#Convert to integer, increment, then back to string p ("100".to_i + 1).to_s #Prints 101</lang>

C

Handling strings of arbitrary sizes:<lang c>#include <stdio.h>

1. include <string.h>
2. include <stdlib.h>

/* Constraints: input is in the form of (\+|-)?[0-9]+

*  and without leading zero (0 itself can be as "0" or "+0", but not "-0");
*  input pointer is realloc'able and may change;
*  if input has leading + sign, return may or may not keep it.
*  The constranits conform to sprintf("%+d") and this function's own output.
*/

char * incr(char *s) { int i, begin, tail, len; int neg = (*s == '-'); char tgt = neg ? '0' : '9';

/* special case: "-1" */ if (!strcmp(s, "-1")) { s[0] = '0', s[1] = '\0'; return s; }

len = strlen(s); begin = (*s == '-' || *s == '+') ? 1 : 0;

/* find out how many digits need to be changed */ for (tail = len - 1; tail >= begin && s[tail] == tgt; tail--);

if (tail < begin && !neg) { /* special case: all 9s, string will grow */ if (!begin) s = realloc(s, len + 2); s[0] = '1'; for (i = 1; i <= len - begin; i++) s[i] = '0'; s[len + 1] = '\0'; } else if (tail == begin && neg && s[1] == '1') { /* special case: -1000..., so string will shrink */ for (i = 1; i < len - begin; i++) s[i] = '9'; s[len - 1] = '\0'; } else { /* normal case; change tail to all 0 or 9, change prev digit by 1*/ for (i = len - 1; i > tail; i--) s[i] = neg ? '9' : '0'; s[tail] += neg ? -1 : 1; }

return s; }

void string_test(const char *s) { char *ret = malloc(strlen(s)); strcpy(ret, s);

printf("text: %s\n", ret); printf(" ->: %s\n", ret = incr(ret)); free(ret); }

int main() { string_test("+0"); string_test("-1"); string_test("-41"); string_test("+41"); string_test("999"); string_test("+999"); string_test("109999999999999999999999999999999999999999"); string_test("-100000000000000000000000000000000000000000000");

return 0; }</lang>output<lang>text: +0

 ->: +1

text: -1

 ->: 0

text: -41

 ->: -40

text: +41

 ->: +42

text: 999

 ->: 1000

text: +999

 ->: 1000

text: 109999999999999999999999999999999999999999

 ->: 110000000000000000000000000000000000000000

text: -100000000000000000000000000000000000000000000

 ->: -99999999999999999999999999999999999999999999</lang>

C++

<lang cpp>// standard C++ string stream operators

1. include <cstdlib>
2. include <string>
3. include <sstream>

// inside a function or method... std::string s = "12345";

int i; std::istringstream(s) >> i; i++; //or: //int i = std::atoi(s.c_str()) + 1;

std::ostringstream oss; if (oss << i) s = oss.str();</lang>

Works with: C++11

<lang cpp>#include <string>

std::string s = "12345"; s = std::to_string(1+std::stoi(s));</lang>

Library: Boost

<lang cpp>// Boost

1. include <cstdlib>
2. include <string>
3. include <boost/lexical_cast.hpp>

// inside a function or method... std::string s = "12345"; int i = boost::lexical_cast<int>(s) + 1; s = boost::lexical_cast<std::string>(i);</lang>

Library: Qt

Uses: Qt (Components:{{#foreach: component$n$|{{{component$n$}}}Property "Uses Library" (as page type) with input value "Library/Qt/{{{component$n$}}}" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process., }})

<lang cpp>// Qt QString num1 = "12345"; QString num2 = QString("%1").arg(v1.toInt()+1);</lang>

Library: MFC

Uses: Microsoft Foundation Classes (Components:{{#foreach: component$n$|{{{component$n$}}}Property "Uses Library" (as page type) with input value "Library/Microsoft Foundation Classes/{{{component$n$}}}" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process., }})

Uses: C Runtime (Components:{{#foreach: component$n$|{{{component$n$}}}Property "Uses Library" (as page type) with input value "Library/C Runtime/{{{component$n$}}}" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process., }})

<lang cpp>// MFC CString s = "12345"; int i = _ttoi(s) + 1; int i = _tcstoul(s, NULL, 10) + 1; s.Format("%d", i);</lang>

All of the above solutions only work for numbers <= INT_MAX. The following works for an (almost) arbitrary large number:

Works with: g++ version 4.0.2

<lang cpp>#include <string>

1. include <iostream>
2. include <ostream>

void increment_numerical_string(std::string& s) {

   std::string::reverse_iterator iter = s.rbegin(), end = s.rend();
   int carry = 1;
   while (carry && iter != end)
   {
       int value = (*iter - '0') + carry;
       carry = (value / 10);
       *iter = '0' + (value % 10);
       ++iter;
   }
   if (carry)
       s.insert(0, "1");

}

int main() {

   std::string big_number = "123456789012345678901234567899";
   std::cout << "before increment: " << big_number << "\n";
   increment_numerical_string(big_number);
   std::cout << "after increment:  " << big_number << "\n";

}</lang>

C#

<lang csharp>string s = "12345"; s = (int.Parse(s) + 1).ToString();</lang>

Clojure

<lang lisp>(str (inc (Integer/parseInt "1234")))</lang>

CMake

CMake performs all arithmetic with numeric strings, through its math() command.

<lang cmake>set(string "1599") math(EXPR string "${string} + 1") message(STATUS "${string}")</lang>

-- 1600

Common Lisp

<lang lisp>(princ-to-string (1+ (parse-integer "1234")))</lang>

D

<lang d>import std.string;

void main() {

   string s = succ("12345");

} </lang>

Something similar can be done in

Library: tango

using the import:

<lang D>import tango.text.convert.Integer;</lang>

Delphi

<lang Delphi>program IncrementNumericalString;

{$APPTYPE CONSOLE}

uses SysUtils;

const

 STRING_VALUE = '12345';

begin

 WriteLn(Format('"%s" + 1 = %d', [STRING_VALUE, StrToInt(STRING_VALUE) + 1]));

 Readln;

end.</lang>

Output:

"12345" + 1 = 123456

DWScript

<lang Delphi>var value : String = "1234"; value := IntToStr(StrToInt(value) + 1); PrintLn(value);</lang>

E

<lang e>__makeInt("1234", 10).next().toString(10)</lang>

Erlang

<lang erlang>integer_to_list(list_to_integer("1336")+1).</lang>

Euphoria

<lang euphoria>include get.e

function val(sequence s)

   sequence x
   x = value(s)
   return x[2]

end function

sequence s

s = "12345" s = sprintf("%d",{val(s)+1})</lang>

Factor

<lang factor>"1234" string>number 1 + number>string</lang>

Fantom

Within 'fansh':

<lang fantom> fansh> a := "123" 123 fansh> (a.toInt + 1).toStr 124 </lang>

Forth

This word causes the number whose string value is stored at the given location to be incremented. The address passed must contain enough space to hold the string representation of the new number. Error handling is rudimentary, and consists of aborting when the string does not contain a numerical value.

The word ">string" takes and integer and returns the string representation of that integer. I factored it out of the definitions below to keep the example simpler.

<lang forth>: >string ( d -- addr n )

 dup >r dabs <# #s r> sign #> ;

inc-string ( addr -- )

 dup count number? not abort" invalid number"
 1 s>d d+ >string rot place ;</lang>

Here is a version that can increment by any value

<lang forth>: inc-string ( addr n -- )

 over count number? not abort" invalid number"
 rot s>d d+  >string rot place ;</lang>

Test the first version like this:

<lang forth>s" 123" pad place pad inc-string pad count type</lang>

And the second one like this:

<lang forth>s" 123" pad place pad 1 inc-string pad count type</lang>

Fortran

Works with: Fortran version 90 and later

Using 'internal' files you can increment both integer and real strings <lang fortran>CHARACTER(10) :: intstr = "12345", realstr = "1234.5" INTEGER :: i REAL :: r

READ(intstr, "(I10)") i  ! Read numeric string into integer i i = i + 1  ! increment i WRITE(intstr, "(I10)") i  ! Write i back to string

READ(realstr, "(F10.1)") r r = r + 1.0 WRITE(realstr, "(F10.1)") r</lang>

F#

<lang fsharp>let next = string( int( "1234" ) + 1 )</lang>

GAP

<lang gap># Using built-in functions Incr := s -> String(Int(s) + 1);

1. Implementing addition
2. (but here 9...9 + 1 = 0...0 since the string length is fixed)

Increment := function(s)

 local c, n, carry, digits;
 digits := "0123456789";
 n := Length(s);
 carry := true;
 while n > 0 and carry do
   c := Position(digits, s[n]) - 1; 
   if carry then
     c := c + 1;
   fi;
   if c > 9 then
     carry := true;
     c := c - 10;
   else
     carry := false;
   fi;
   s[n] := digits[c + 1];
   n := n - 1;
 od;

end;

s := "2399"; Increment(s); s;

1. "2400"</lang>

Go

Concise: <lang go>package main import "fmt" import "strconv" func main() {

 i, _ := strconv.Atoi("1234")
 fmt.Println(strconv.Itoa(i + 1))

}</lang> More: <lang go>package main

import (

   "big"
   "fmt"
   "strconv"

)

func main() {

   // integer
   is := "1234"
   fmt.Println("original:   ", is)
   i, err := strconv.Atoi(is)
   if err != nil {
       fmt.Println(err)
       return
   }
   // assignment back to original variable shows result is the same type.
   is = strconv.Itoa(i + 1)
   fmt.Println("incremented:", is)

   // error checking worthwhile
   fmt.Println()
   _, err = strconv.Atoi(" 1234") // whitespace not allowed
   fmt.Println(err)
   _, err = strconv.Atoi("12345678901")
   fmt.Println(err)
   _, err = strconv.Atoi("_1234")
   fmt.Println(err)
   _, err = strconv.Atof64("12.D34")
   fmt.Println(err)

   // float
   fmt.Println()
   fs := "12.34"
   fmt.Println("original:   ", fs)
   f, err := strconv.Atof64(fs)
   if err != nil {
       fmt.Println(err)
       return
   }
   // various options on Ftoa64 produce different formats.  All are valid
   // input to Atof64, so result format does not have to match original
   // format.  (Matching original format would take a lot of code.)
   fs = strconv.Ftoa64(f+1, 'g', -1)
   fmt.Println("incremented:", fs)
   fs = strconv.Ftoa64(f+1, 'e', 4)
   fmt.Println("what format?", fs)

   // complex
   // strconv package doesn't handle complex types, but fmt does.
   // (fmt can be used on ints and floats too, but strconv is more efficient.)
   fmt.Println()
   cs := "(12+34i)"
   fmt.Println("original:   ", cs)
   var c complex128
   _, err = fmt.Sscan(cs, &c)
   if err != nil {
       fmt.Println(err)
       return
   }
   cs = fmt.Sprint(c + 1)
   fmt.Println("incremented:", cs)

   // big integers have their own functions
   fmt.Println()
   bs := "170141183460469231731687303715884105728"
   fmt.Println("original:   ", bs)
   var b, one big.Int
   _, ok := b.SetString(bs, 10)
   if !ok {
       fmt.Println("big.SetString fail")
       return
   }
   one.SetInt64(1)
   bs = b.Add(&b, &one).String()
   fmt.Println("incremented:", bs)

}</lang> Output:

original:    1234
incremented: 1235

parsing " 1234": invalid argument
parsing "12345678901": numerical result out of range
parsing "_1234": invalid argument
parsing "12.D34": invalid argument

original:    12.34
incremented: 13.34
what format? 1.3340e+01

original:    (12+34i)
incremented: (13+34i)

original:    170141183460469231731687303715884105728
incremented: 170141183460469231731687303715884105729

Golfscript

<lang golfscript>~)`</lang> With a test framework to supply a number: <lang golfscript>"1234" ~)` p</lang>

Groovy

Solution: <lang groovy>println ((("23455" as BigDecimal) + 1) as String) println ((("23455.78" as BigDecimal) + 1) as String)</lang>

Output:

23456
23456.78

Haskell

<lang haskell>(show . (+1) . read) "1234"</lang>

HicEst

<lang hicest>CHARACTER string = "123 -4567.89"

  READ( Text=string) a,   b
  WRITE(Text=string) a+1, b+1 ! 124 -4566.89</lang>

Icon and Unicon

Icon and Unicon will automatically coerce type conversions where they make sense. Where a conversion can't be made to a required type a run time error is produced.

<lang Icon>s := "123" # s is a string s +:= 1# s is now an integer</lang>

IDL

<lang idl>str = '1234' print, string(fix(str)+1)

==> 1235</lang>

In fact, IDL tries to convert types cleverly. That works, too:

<lang idl>print, '1234' + 1

==> 1235</lang>

Inform 7

This solution works for numbers that fit into a single word (16-bit signed int for Z-machine, 32-bit signed int for Glulx virtual machine). <lang inform7>Home is a room.

To decide which indexed text is incremented (T - indexed text): let temp be indexed text; let temp be the player's command; change the text of the player's command to T; let N be a number; if the player's command matches "[number]": let N be the number understood; change the text of the player's command to temp; decide on "[N + 1]".

When play begins: say incremented "12345"; end the story.</lang>

J

<lang j>incrTextNum=: >:&.".</lang>

Note that in addition to working for a single numeric value, this will increment multiple values provided within the same string, on a variety of number types and formats including rational and complex numbers. <lang j> incrTextNum '34.5' 35.5

  incrTextNum '7 0.2 3r5 2j4 5.7e_4'

8 1.2 1.6 3j4 1.00057</lang>

Note also that the result here is a list of characters, and not a list of integers, which becomes obvious when you manipulate the result. For example, consider the effect of reversing the contents of the list:

<lang j> |.incrTextNum'123 456' 754 421

  |.1+123 456

457 124</lang>

Java

When using Integer.parseInt in other places, it may be beneficial to call trim on the String, since parseInt will throw an Exception if there are spaces in the String. <lang java>String s = "12345"; s = String.valueOf(Integer.parseInt(s) + 1);</lang>

JavaScript

<lang javascript>var s = "12345"; s = (Number(s) + 1).toString(); </lang>

K

"." is a built-in function that evaluates a valid K expression.

<lang K> 1 + ."1234" 1235

  1 + ."1234.56"

1235.56

  / As a function
  inc:{1 + . x}
  inc "1234"

1235</lang>

Some other examples. <lang K> 1 + .:' ("1";"2";"3";"4") 2 3 4 5

  1 + . "123 456"

124 457

  . "1","+","-10"

-9</lang>

LaTeX

<lang latex>\documentclass{article}

% numbers are stored in counters \newcounter{tmpnum}

% macro to increment a string (given as argument) \newcommand{\stringinc}[1]{% \setcounter{tmpnum}{#1}% setcounter effectively converts the string to a number \stepcounter{tmpnum}% increment the counter; alternatively: \addtocounter{tmpnum}{1} \arabic{tmpnum}% convert counter value to arabic (i.e. decimal) number string }

%example usage \begin{document} The number 12345 is followed by \stringinc{12345}. \end{document}</lang>

Liberty BASIC

<lang lb>' [RC] Increment a numerical string.

o$ ="12345" print o$

v =val( o$) o$ =str$( v +1) print o$

end</lang>

Logo

Logo is weakly typed, so numeric strings can be treated as numbers and numbers can be treated as strings. <lang logo>show "123 + 1  ; 124 show word? ("123 + 1) ; true</lang>

Logtalk

<lang logtalk>number_chars(Number, "123"), Number2 is Number+1, number_chars(Number2, String2)</lang>

Lua

<lang lua>print(tonumber("2345")+1)</lang>

M4

M4 can handle only integer signed 32 bit numbers, and they can be only written as strings <lang m4>define(`V',`123')dnl define(`VN',`-123')dnl eval(V+1) eval(VN+1)</lang>

If the expansion of any macro in the argument of eval gives something that can't be interpreted as an expression, an error is raised (but the interpretation of the whole file is not stopped)

Mathematica

<lang Mathematica>Print[FromDigits["1234"] + 1]</lang>

MATLAB

<lang MATLAB>function numStr = incrementNumStr(numStr)

   numStr = num2str(str2double(numStr) + 1);

end</lang>

MAXScript

<lang maxscript>str = "12345" str = ((str as integer) + 1) as string</lang>

Metafont

<lang metafont>string s; s := "1234"; s := decimal(scantokens(s)+1); message s;</lang>

Modula-2

<lang modula2>MODULE addstr;

IMPORT InOut, NumConv, Strings;

VAR str1, str2  : Strings.String;

       num             : CARDINAL;
       ok              : BOOLEAN;

BEGIN

 str1 := "12345";
 InOut.Write ('"');    InOut.WriteString (str1);       InOut.WriteString ('" + 1 = ');
 NumConv.Str2Num (num, 10, str1, ok);
 INC (num);
 NumConv.Num2Str (num, 10, str2,  ok);
 InOut.WriteString (str2);
 InOut.WriteLn

END addstr.</lang>

"12345" + 1 = 12346

Nemerle

<lang Nemerle>mutable str = "12345"; str = $"$(Int32.Parse(str)+1)";</lang>

Oberon-2

<lang oberon2>MODULE addstr;

IMPORT Out, Strings;

VAR str1, str2  : ARRAY 9 OF CHAR;

       num, pos        : INTEGER;
       carry           : BOOLEAN;
       ch              : CHAR;

BEGIN

 str1 := "9999";
 Out.Char ('"');       Out.String (str1);      Out.String ('" + 1 = ');
 num := Strings.Length (str1) - 1;
 pos := num;
 IF  str1 [0] = '9'  THEN  INC (pos)  END;
 str2 [pos + 1] := 0X;
 carry := TRUE;
 REPEAT
   ch := str1 [num];
   IF  carry  THEN
     ch := CHR (ORD (ch) + 1)
   END;
   IF  ch > '9'  THEN
     carry := TRUE;
     ch := '0'
   ELSE
     carry := FALSE
   END;
   str2 [pos] := ch;
   DEC (num);
   DEC (pos)
 UNTIL num < 0;
 IF  carry  THEN  str2 [0] := '1'  END;
 Out.String (str2);
 Out.Ln

END addstr.</lang> Producing:

jan@Beryllium:~/Oberon/obc$ Add
"12345" + 1 = 12346
"9999" + 1 = 10000

Modula-3

Modula-3 provides the module Scan for lexing. <lang modula3>MODULE StringInt EXPORTS Main;

IMPORT IO, Fmt, Scan;

VAR string: TEXT := "1234";

   num: INTEGER := 0;

BEGIN

 num := Scan.Int(string);
 IO.Put(string & " + 1 = " & Fmt.Int(num + 1) & "\n");

END StringInt.</lang> Output:

1234 + 1 = 1235

MUMPS

Just add. <lang MUMPS>

SET STR="123"
WRITE STR+1

</lang>

Objective-C

<lang objc>NSString *s = @"12345"; int i = [s intValue] + 1; s = [NSString stringWithFormat:@"%i", i]</lang>

NetRexx

In concert with Rexx, NetRexx can use typeless variables. Typeless variable support is provided through the default NetRexx Rexx object. Values are stored as variable length character strings and can be treated as either a string or a numeric value, depending on the context in which they are used. <lang NetRexx>/* NetRexx */

options replace format comments java crossref savelog symbols nobinary

numbers = '12345' say numbers numbers = numbers + 1 say numbers

return </lang>

Output

12345
12346

Objeck

<lang objeck> s := "12345"; i := int->ToInt(s) + 1; s := i->ToString(); </lang>

OCaml

<lang ocaml>string_of_int (succ (int_of_string "1234"))</lang>

Octave

We convert the string to a number, increment it, and convert it back to a string.

<lang octave>nstring = "123"; nstring = sprintf("%d", str2num(nstring) + 1); disp(nstring);</lang>

OpenEdge/Progress

<lang progress>DEFINE VARIABLE cc AS CHARACTER INITIAL "12345".

MESSAGE

  INTEGER( cc ) + 1 

VIEW-AS ALERT-BOX.</lang>

Oz

<lang oz>{Int.toString {String.toInt "12345"} + 1}</lang>

PARI/GP

<lang parigp>foo(s)=Str(eval(s)+1);</lang>

Pascal

See Delphi

Perl

<lang perl>my $s = "12345"; $s++;</lang>

Perl 6

Works with: Rakudo version #22 "Thousand Oaks"

<lang perl6>my $s = "12345"; $s++;</lang>

PHP

<lang php>$s = "12345"; $s++;</lang>

PicoLisp

<lang PicoLisp>(format (inc (format "123456")))</lang>

Pike

<lang Pike>string number = "0"; number = (string)((int)number+1); Result: "1"</lang>

PL/I

<lang PL/I> declare s picture '999999999'; s = '123456789'; s = s + 1; put skip list (s); </lang>

Plain TeX

<lang tex>\newcount\acounter \def\stringinc#1{\acounter=#1\relax% \advance\acounter by 1\relax% \number\acounter} The number 12345 is followed by \stringinc{12345}. \bye</lang>

The generated page will contain the text:

The number 12345 is followed by 12346.

Pop11

<lang pop11>lvars s = '123456789012123456789999999999'; (strnumber(s) + 1) >< -> s;</lang>

PowerShell

The easiest way is to cast the string to int, incrementing it and casting back to string: <lang powershell>$s = "12345" $t = [string] ([int] $s + 1)</lang> One can also take advantage of the fact that PowerShell casts automatically according to the left-most operand to save one cast: <lang powershell>$t = [string] (1 + $s)</lang>

Prolog

Works with SWI-Prolog. <lang Prolog>incr_numerical_string(S1, S2) :- string_to_atom(S1, A1), atom_number(A1, N1), N2 is N1+1, atom_number(A2, N2), string_to_atom(S2, A2). </lang> Output : <lang Prolog> ?- incr_numerical_string("123", S2). S2 = "124". </lang>

PureBasic

<lang PureBasic>string$="12345" string$=Str(Val(string$)+1) Debug string$</lang>

Python

Works with: Python version 2.3, 2.4, 2.5, and 2.6

<lang python>next = str(int('123') + 1)</lang>

R

<lang r>s = "12345" s <- as.character(as.numeric(s) + 1)</lang>

REBOL

<lang REBOL>REBOL [ Title: "Increment Numerical String" Author: oofoe Date: 2009-12-23 URL: http://rosettacode.org/wiki/Increment_numerical_string ]

Note the use of unusual characters in function name. Also note that

because REBOL collects terms from right to left, I convert the

string argument (s) to integer first, then add that result to one.

s++: func [s][to-string 1 + to-integer s]

Examples. Because the 'print' word actually evaluates the block

(it's effectively a 'reduce' that gets printed space separated),

it's possible for me to assign the test string to 'x' and have it

printed as a side effect. At the end, 'x' is available to submit to

the 's++' function. I 'mold' the return value of s++ to make it

obvious that it's still a string.

print [x: "-99" "plus one equals" mold s++ x] print [x: "42" "plus one equals" mold s++ x] print [x: "12345" "plus one equals" mold s++ x]</lang>

Output:

-99 plus one equals "-98"
42 plus one equals "43"
12345 plus one equals "12346"

Retro

<lang Retro>"123" toNumber 1+ toString</lang>

REXX

Rexx, like many other scripting languages, uses typeless variables. Typeless variables are stored as variable length character strings and can be treated as either a string or a numeric value, depending on the context in which they are used.

<lang rexx> count = "3" /* Typeless variables are all strings */ count = count + 1 /* Variables in a numerical context are treated as numbers */ say count </lang>

Ruby

If a string represents a number, the succ method will increment the number: <lang ruby>'1234'.succ #=> '1235' '99'.succ #=> '100'</lang>

Scala

The string needs to be converted to a numeric type. BigDecimal should handle most numeric strings. We define a method to do it.

<lang scala>implicit def toSucc(s: String) = new { def succ = BigDecimal(s) + 1 toString }</lang>

Usage:

scala> "123".succ
res5: String = 124

Scheme

<lang scheme>(number->string (+ 1 (string->number "1234")))</lang>

Sed

Reads a decimal integer from stdin and outputs the same with the magnitude incremented by one.

(TODO: Since it deals only with the magnitude, the result is incorrect for negative numbers—though adding this support is definitely possible.)

The routine starts by suffixing the input number with a carry mark (a : in this case) indicating that the digit to its left still needs to be incremented. In a loop, the following happens:

• If there is a carry mark on the far left, replace it with a 1.
• If there are no more carry marks, exit the loop.
• Hold the current number. (h)
• Extract the digit to the left of the first carry mark. (s)
• Replace the digit with the same digit incremented by one, with 9 incrementing to a carry mark (i.e. 10). (y)
• If the result of such replacement was a carry mark, suffix the mark with a 0, indicating that the digit has rolled over and the digit to the left must be incremented. (s)
• Retrieve the held number (G) and replace the first carry mark and the digit to its left with the result of the computation. (s)
• Repeat. (b)

<lang sed>s/^.*$/&:/

bubble

s/^:/1/ /.:/ {

   h
   s/^.*\(.\):.*$/\1/
   y/0123456789/123456789:/
   s/:/:0/
   G
   s/\(.*\)\n\(.*\).:\(.*\)$/\2\1\3/
   b bubble

}</lang>

Seed7

<lang seed7>var string: s is "12345";

s := str(succ(integer parse s));</lang>

Slate

<lang slate>((Integer readFrom: '123') + 1) printString</lang>

Smalltalk

<lang smalltalk>('123' asInteger + 1) printString</lang>

SNOBOL4

<lang snobol4>

    output = trim(input) + 1
    output = "123" + 1

end</lang>

Input

123

Output

124
124

Standard ML

<lang sml>Int.toString (1 + valOf (Int.fromString "1234"))</lang>

Tcl

In the end, all variables are strings in Tcl. A "number" is merely a particular interpretation of a string of bytes. <lang tcl>set str 1234 incr str</lang>

TI-89 BASIC

<lang ti89b>string(expr(str)+1)</lang>

Toka

<lang toka>" 100" >number drop 1 + >string</lang>

TUSCRIPT

<lang tuscript> $$ MODE TUSCRIPT teststring="0'1'-1'12345'10000000'-10000000" LOOP/CLEAR n=teststring n=n+1 PRINT n ENDLOOP </lang> Output:

1
2
0
12346
10000001
-9999999 

TXR

An actual implementation of what the task says: incrementing a numerical string. (Not: converting a string to a number, then incrementing the number, then converting back to string.)

<lang txr>@(do (defun inc-num-str (str-in)

      (let ((len (length str-in))
            (str (copy-str str-in)))
        (for ((i (- len 1)))
             ((>= i 0) `1@str`)
             ((dec i))
          (let ((dig (chr-str str i)))
            (if (<= (inc dig) #\9)
              (progn (chr-str-set str i dig)
                     (return str))
              (chr-str-set str i #\0)))))))

@(bind a @(inc-num-str "9999")) @(bind b @(inc-num-str "1234")) </lang>

$ ./txr incnum.txr 
a="10000"
b="1235"

UNIX Shell

Traditional Unix shell does not directly support arithmetic operations, so external tools, such as expr are used to perform arithmetic calculations when required. The following example demonstrates how a variable can be incremented by using the expr function:

Works with: Bourne Shell

<lang bash># All variables are strings within the shell

1. Although num look like a number, it is in fact a numerical string

num=5 num=`expr $num + 1` # Increment the number</lang>

The Korn Shell and some newer shells do support arithmetic operations directly, and several syntax options are available:

Works with: bash

Works with: ksh93

Works with: pdksh

Works with: zsh

<lang bash>num=5 let num=num+1 # Increment the number let "num = num + 1" # Increment again. (We can use spaces inside quotes) ((num = num + 1)) # This time we use doublebrackets let num+=1 # This time we use += let "num += 1" ((num += 1))</lang>

Works with: ksh93

Works with: pdksh

Works with: zsh

<lang bash>integer num=5 # Declare an integer... num=$num+1 # ...then increment without the let keyword.</lang>

C Shell

The @ assignment command uses strings as integers. <lang csh>@ num = 5 @ num += 1</lang>

Ursala

<lang Ursala>#import nat

instring = ~&h+ %nP+ successor+ %np@iNC # convert, do the math, convert back</lang> test program: <lang Ursala>#cast %sL

tests = instring* <'22435','4','125','77','325'></lang> output:

<'22436','5','126','78','326'>

Vedit macro language

This example increments numeric string by converting it into numeric value, as most other language examples do. The string is located in text register 10. <lang vedit>itoa(atoi(10)+1, 10)</lang>

The following example increments unsigned numeric string of unlimited length. The current line in the edit buffer contains the string. <lang vedit>EOL do {

   if (At_BOL) {

Ins_Char('1') // add new digit Break

   }
   Char(-1)
   #1 = Cur_Char+1		// digit
   #2 = 0			// carry bit
   if (#1 > '9') {

#1 = '0' #2 = 1

   }
   Ins_Char(#1, OVERWRITE)
   Char(-1)

} while (#2) // repeat until no carry</lang>

VBA

The easy method assumes that the number can be represented as a Long integer: <lang VBA> Public Function incr(astring As String) As String 'simple function to increment a number string

  incr = CStr(CLng(astring) + 1)

End Function </lang> Examples:

print incr("345343434")
345343435
print incr("-10000000")
-9999999

The long version handles arbitrary-length strings: <lang VBA> Public Function Lincr(astring As String) As String 'increment a number string, of whatever length 'calls function "increment" or "decrement" Dim result As String

'see if it is a negative number If left$(astring, 1) = "-" Then

 'negative x: decrease |x| by 1, then add "-"
 '(except if the result is zero)
 result = decrement(Mid$(astring, 2))
 If result <> "0" Then result = "-" & result

Else

 '0 or positive x: increase x by 1
 If left$(astring, 1) = "+" Then  'allow a + before the number
   result = increment(Mid$(astring, 2))
 Else
   result = increment(astring)
 End If

End If Lincr = result End Function

Public Function increment(astring) As String Dim result As String 'increment a string representing a positive number 'does not work with negative numbers carry = 1 L = Len(astring) result = "" For j = L To 1 Step -1

 digit = Val(Mid$(astring, j, 1)) + carry
 If digit > 9 Then
   digit = digit - 10
   carry = 1
 Else
   carry = 0
 End If
 result = CStr(digit) & result

Next If carry = 1 Then result = CStr(carry) & result increment = result End Function

Public Function decrement(astring) As String Dim result As String 'decrement a string representing a positive number 'does not work with zero or negative numbers borrow = 1 L = Len(astring) result = "" For j = L To 1 Step -1

 digit = Val(Mid$(astring, j, 1)) - borrow
 If digit < 0 Then
   digit = digit + 10
   borrow = 1
 Else
   borrow = 0
 End If
 result = CStr(digit) & result

Next 'remove leading zero, if necessary If (Len(result) > 1) And (left$(result, 1) = "0") Then result = Mid$(result, 2) decrement = result End Function </lang> Examples:

print Lincr("99999999999999999")
100000000000000000
print Lincr("-10000000000000000")
-9999999999999999
print Lincr("-1")
0
print Lincr("0")
1
print Lincr("+1234567890987654321009")
1234567890987654321010

Visual Basic .NET

<lang vbnet> Dim s As String = "123"

   s = CStr(CInt("123") + 1)
   ' or
   s = (CInt("123") + 1).ToString</lang>