Add without addition (or any of the 4 basic arithmetic operators)

Question

Problem:

Your goal is to add two input numbers without using any of the following math operators: +,-,*,/.

Additionally, you can't use any built-in functions that are designed to replace those math operators.

Scoring:

Smallest code (in number of bytes) wins.

Update

Most of the programs i've seen either concatenate two arrays containing their numbers, or make first number of a character, append second number characters, then count them all.

Shortest array counter: APL with 8 chars, by Tobia

Shortest array concatenation: Golfscript with 4 chars, by Doorknob

Shortest logarithmic solution: TI-89 Basic with 19 chars, by Quincunx

Integration solution: Mathematica with 45 chars, by Michael Stern

Coolest, in my opinion: bitwise operators in javascript, by dave

Answer 1

PowerShell, 22 bytes

($args|%{,1*$_}).Count

Try it online!

Where * is an repeat element operator.

Answer 2

Python 3, 38 bytes

f=lambda a,b:b and f(a^b,(a&b)<<1)or a

Try it online!

Uses bitwise operations recursively to work out the sum.
Works with some negative numbers (works as long as both are positive, or their sum is less than zero).

Answer 3

Vyxal, 8 6 bytes

ẋ??ẋJL

Try it Online!

I can't get base-1 to work.

-2 thx to lyxal

Answer 4

Perl, 23

Since the question does not specify input types and formats, we assume that the input will be natural numbers in the unary number system.

chop($s=<>);print $s.<>

For example, if we are to sum 2 (in base 10) and 3 (in base 10), we input 11 and 111 and we get 11111.

Answer 5

Python 16 (Using Cheat)

print sum((a,b))

Python 36 (Using Tricks)

print len("%%0%dd%%0%dd"%(5,7)%(0,0))

Answer 6

Perl 28

print length('0'x$a.'0'x$b);

Answer 7

Javascript - 43, 39, 13 and 4 characters

• The second number must be integer and non-negative.
• The first number can be negative or not an integer.

If the code must take the input and show output, here it is, in 43 characters:

a=prompt,x=a(),y=a();while(y--)x++;alert(x)

But if the code need not take input and output, and just a function that does the sum in needed, then we can do in 39 characters:

function s(x,y){while(y--)x++;return x}

But if you just need an instruction to add two variables x and y (and don't bother in destroying the original value of both), here it is in 13 characters:

while(y--)x++

And, as suggested by @Ismael Miguel (althought he was not exactly suggesting this), by really abusing the rules underspecification, we can note that only +, -, * and / operators were forbidden, but += was not, so it is allowed (it is not a built-in function either, since it is not even a function). This way, we can express the instruction with just 4 characters (and it will always work with negatives and non-integers too for both values):

y+=x

Answer 8

PHP

This function works recursively for positive interger values for x and y.

function plus($x,$y) {
    return $x?ceil(plus(--$x,$y).".1"):$y;
}

The result of

echo plus(3,4);

is

7

Answer 9

JavaScript [32 bytes]

Array(a).concat(Array(b)).length

This code adds two non-negative variables a and b. Test in any browser console.

Answer 10

K, 11

{#,/!:'x,y}

Creates two vectors of length x and y (the two inputs), raze into a single list and then get the length.

Answer 11

x86 machine code (32 bit): 3 bytes

here provided in hexadecimal form for ease of reading:

8d 04 18

(no, it's not add eax,ebx)

Answer 12

Assembly (x86),

Taking a shot at this, not sure if it breaks rule 2 set by the question.

First, assume input 1 was loaded into %eax, and input 2 was loaded into %ecx

leal    (%eax, %ecx), %eax

EDIT: apparently the scale defaults to one, so I'll just take that off there.

Answer 13

Maxima, 12

[a,b].[1,1];

I just made use of the dot operator to multiply matrices. In this case I get the inner product of the vectors (a,b) and (1,1) which is of course a+b.

Answer 14

Excel - 31

(presuming numbers in cells A1 and A2)

=LEN(REPT("X",A1)&REPT("X",A2))

The digital equivalent of counting on fingers. :)

Answer 15

Prolog (SWI), 49 bytes

s(0,Y,Y).
s(X,Y,S):-succ(W,X),s(W,Y,R),succ(R,S).

Defines a predicate s that takes in the two numbers and unifies the result with its third argument (which is the standard way of "returning" a value in Prolog). On Linux, put the code in a file and pass it to swipl -qs; then enter queries at the prompt. Sample run:

dlosc@dlosc:~/golf$ swipl -qs addWithoutAdding.prolog
?- s(3,5,X).
X = 8 .

?- s(14,42,X).
X = 56 .

This actually seems like a fairly Prolog-ish way to do addition--the language does have arithmetic operations, but they've always felt bolted-on to me.

• If the first argument is 0, unify the result with the second argument.
• Otherwise, let W be the predecessor of X (the succ predicate can go either direction), let R be the result of adding W and Y, and let S be the successor of R.

Because of how succ works, only nonnegative integers are supported.

Answer 16

Python 3, 46 Bytes

def s(a,b):
 for i in range(b):a=-~a
 return a

Answer 17

SmileBASIC, 55 bytes

INPUT A,B
SPSET.,0SPROT.,A
SPANIM.,12,1,B
WAIT?SPROT(0)

Doesn't use any mathematical or string functions

Explained:

INPUT A,B 'input
SPSET 0,0 'create sprite 0 with definition 0
SPROT 0,A 'set the angle of sprite 0 to A degrees
SPANIM 0,"R+",1,B 'rotate sprite 0 by B degrees relative to its current rotation
WAIT 'wait 1 frame so sprite can update
PRINT SPROT(0) 'output the angle of sprite 0

Answer 18

Jelly - 2,4 bytes

‘¡

If we're allowed to increment, then this increments x y times.

,RFL

,R create a nested list [[1,2,...,x],[1,2...,y]]. FL flatten the list and count the elements to get your number.

Answer 19

PowerShell, 31 bytes

param($a,$b)(,1*$a+,1*$b).Count

Try it online!

The + and * are not arithmetic signs, but array concatenation and element repetition operators respectively. Big thanks to @mazzy for handling 0.

Answer 20

Keg -hr, 10 bytes

(2|(¿|0))!

Try it online!

Places a whole bunch of 0's onto the stack, and then prints the length of the stack. It then uses the hr flag to print the top of the stack raw.

Answer 21

Ruby, 41 20 bytes

->a,b{(-a...b).size}

Try it online!

Answer 22

MarioLANG, 31 bytes

;
)
;
>[!(
"=#:
  -
) (
!+<
#="

Try it online!

Note: + and - are INCREMENT and DECREMENT respectively, NOT addition and subtraction.

Answer 23

Octave, 62 39 37 bytes

@(a,b)fix(toc(tic,pause(a),pause(b)))

Unsigned integers only. Try it online!

-2 thanks to @MarcinKonowalczyk

Answer 24

Python 48 47 Bytes

print(len({*range(x)}|{(j,)for j in range(y)})

Does not use +, even as concat. 41 40 without print.

Removed space before for thanks to user8397947.

Answer 25

Excel, 29 bytes

=LEN(CONCAT(REPT("x",A1:A2)))

Creates two strings of "x" repeated A1 and A2 times; concatenates the two strings and returns the length of the concatenated string. No built-in sum or sum-like functions.

Answer 26

int Ad(int a,int b){while(b){int c=a & b;a=a ^ b;b=c<<1;}return a;}

Answer 27

Objective-C - Base 1 & Base 10

Actually a fun little project... converted everything to base-1 then just made it a string and took the length. In base one everything is zeros so 5 would be 00000 and 3 would be 000 so I just made two strings of the input in base-one, appended the strings, then printed the length of the string (which converts base 1 to base 10)

Assuming positive integers for inputs *(Note: calculation takes as many seconds as the sum of the integers inputted)

---

Golf version (644 characters):

int i1=#;int i2=#;NSString *h;BOOL f1;BOOL f2;[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(a1) userInfo:nil repeats:i1];[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(a2) userInfo:nil repeats:i2];[NSTimer scheduledTimerWithTimeInterval:i1 target:self selector:@selector(s1) userInfo:nil repeats:0];[NSTimer scheduledTimerWithTimeInterval:i2 target:self selector:@selector(s2) userInfo:nil repeats:0];-(void)a1{h=[h stringByAppendingString:@"0"];}-(void)a1{h=[h stringByAppendingString:@"0"];}-(void)s1{f1=1;[self p];}-(void)s2{f2=1;[self p];}-(void)p{if((f1)&&(f2)){NSLog(@"%i",h.length);}}

---

Understandable version (1210 characters):

int input1 = #;//these can be any positive integer
int input2 = #;//these can be any positive integer
NSString *holder = @"";
BOOL finishedAddingFirst = NO;
BOOL finishedAddingSecond = NO;

[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(addFirst) userInfo:nil repeats:input1];
[NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(addSecond) userInfo:nil repeats:input2];
[NSTimer scheduledTimerWithTimeInterval:input1 target:self selector:@selector(stopAddingFirst) userInfo:nil repeats:0];
[NSTimer scheduledTimerWithTimeInterval:input2 target:self selector:@selector(stopAddingSecond) userInfo:nil repeats:0];

-(void)addFirst {
    holder = [holder stringByAppendingString:@"0"];
}
-(void)addSecond {
    holder = [holder stringByAppendingString:@"0"];
}

-(void)stopAddingFirst {
    finishedAddingFirst = YES;
    [self printFinalAnswer];
}
-(void)stopAddingSecond {
    finishedAddingSecond = YES;
    [self printFinalAnswer];
}

-(void) printFinalAnswer {
    if ((finishedAddingFirst) && (finishedAddingSecond)) {
        NSLog(@"Base-One Sum: %@", holder);
        int output = (int)[holder length];
        NSLog(@"Base-Ten Sum: %i", output);
    }
}

Answer 28

Javascript/JScript 78 76 bytes:

I know this is a long answer, but here is another approach:

function(a,b,c,d,l){c=[],d=[];c[l='length']=a+!!a,d[l]=b+!!b;return(c+d)[l]}

How this works:

It creates 2 arrays with size a+!!a and b+!!b.

I know it has the + in there, but it is 'adding' a Number with a Boolean value.

Basically, it isn't an arithmetic operator anymore!

In the return, it will convert both arrays to string and concatenate them.

To run this, just wrap it in (), add (n1,n2) to the end and you will have the result.

Notice:

It CANNOT handle negative numbers, NaN, Infinity and other non-numeric inputs.

Answer 29

AutoHotkey - 54 Bytes

This accepts two command line parameters and outputs the result as an error message.

For each command line parameter, it runs a loop with that number and in each iteration, it concatenates one character to a string, then it outputs the length of the string.

It outputs it as an error message because the command to throw an error message is shorter than the commands that show a message box or send something to standard output.

a=a
loop,%1%
b.=a
loop,%2%
b.=a
throw % StrLen(b)

Answer 30

F# - 36

(String('a',a)+String('b',b)).Length

The + here is not addition, but string concatenation.