Use this tag for questions about using, storing or manipulating integral values of all types and sizes, including concerns about overflow. Not for code that casually happens to use integers.

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3
votes
0answers
36 views

Safe, fully standards-following integer abs in C

Here's a bit tricky one, because AFAIK there is no existing platform, where conditionally compiled part of the code would actually get included by compiler, so it is entirely up to the human review to ...
4
votes
1answer
39 views

Multiple base numbers parser

This code is a Parser that parses numbers according to R5RS. #b1001 - binary #o2127 - octal #h02d - hexadecimal #d1231 - decimal 3923 - decimal It is ...
3
votes
1answer
52 views

Turning an Integer into an array of ints

My goal here is pretty simple, I want to turn a number like 12435987234 into an array of integers in reverse order. So that would look like: ...
10
votes
4answers
983 views

Arabic to Greek numeral converter, 1 - 10

One of the things that's straight-forward in JavaScript is Unicode support. If you want to return ϝ (lowercase digamma, not a simple ...
4
votes
3answers
53 views

Convert a number into a different base and return as string

I wanted to write a function that would take a long long int argument as well as a base and it would convert that number into an equivalent number in a different ...
11
votes
4answers
594 views

Detecting arithmetic overflow in C with NASM

This snippet is about detecting whether the carry flag is set or cleared. I work on Mac OSX, so my snippet supports Mac only. First, we need a routine that does the job: func.s: ...
11
votes
6answers
2k views

Converting a string to an Integer in C

I'm learning C and one of the questions I've been asked is converting a string to an integer. The code I've written supports converting from a string in any base up to 16/hex to an integer. There is ...
16
votes
2answers
168 views

Fast 32x32 bit multiply on ARM M0

I have a time-critical calculation running on an ARM Cortex-M0. This is the fastest 32x32 bit -> 64 bit multiplication that I can come up with. The following C compiles almost 1-1 to assembly ...
2
votes
0answers
36 views

Recursive implementation of integer partition without re-arrangement

Problem: Integer partition without re-arrangement Input: An arrangement S of nonnegative numbers {s1, . . . , sn} and an ...
5
votes
1answer
97 views

Function to convert a decimal number as a string to hexadecimal

I am designing a cipher and need to convert between bases repeatedly in a loop. I have optimized the everything else, but I'm not too familiar with C++ code, and and am trying to figure out how to ...
11
votes
2answers
196 views

Diffie-Hellman in JavaScript

Diffie-Hellman is a key exchange that allows 2 people to share a symmetric key without interaction beforehand. First, a person shares an equation; in this case, we use: $$3^x \mod{17}$$ Next, each ...
8
votes
2answers
115 views

Implementing min of 3 numbers in Mic-1 code

I have the following algorithm to find a minimum of three input numbers: ...
7
votes
2answers
118 views

All arithmetic operator functions (+, -, *, /, %) coded only using bitwise operators in C

Here's all the functions in C that does all the arithmetic operators without using arithmetic operators themselves, mostly using bitwise operators. Recursive functions and comparison operators are ...
10
votes
3answers
355 views

Binary Converting Code

I made a program that converts a decimal number given from the user, and converts it to a binary number. For example, if I entered 2, it would return 10. It then, counts the amount of ones and zeros ...
2
votes
3answers
134 views

Long arithmetic addition in JS

The implementation of the algorithm which adds two number in string form with arithmetic rules. ...
5
votes
1answer
43 views

Floor and Ceiling to specified int

This relates to Round to specified int but I'm separating these methods out since they're technically different. Is there a method that already performs a custom floor and ceiling to a specified ...
2
votes
1answer
72 views

Round to specified int

This accepts values from a user that needs to show up in a intervals of some number. In this case, we will say intervals of 5. Is there a better way to do this? ...
10
votes
5answers
862 views

Maximum product of 3 integers in an int array

I want to find the maximum product that can be obtained from any 3 integers in an integer array. The optimal solution has time complexity of \$O(n)\$ and space complexity of \$O(1)\$. I managed to ...
1
vote
1answer
45 views

Text representation for numbers with python

Simple function which returns a text representation for numbers in range [1...1000]. ...
11
votes
7answers
537 views

Numbers to byte-arrays and back

As the title explains, this is a series of extension methods that convert certain numeric types to and from byte-arrays, for certain actions which work better on byte-array types than numeric types. ...
3
votes
5answers
914 views

Two integers x & y

Given two int values, print whichever value is larger. However if the two values have the same remainder when divided by 5, then the print the smaller value. However, in all cases, if the two values ...
7
votes
4answers
240 views

Add one to a very large integer

I was asked to implement this in an interview a while back. I didn't pass the interview, mostly likely because it took me far too long to do. However, I'm interested to know how well implemented the ...
3
votes
1answer
159 views

Little/Big Endian conversion

I wanted to make sure that my code is properly converting between the two endians. Here is the code where I read in an integer: ...
18
votes
11answers
5k views

Checking if two numbers have the same sign

Is there a more elegant way than the following to check if two numbers have the same sign? ...
0
votes
2answers
51 views

Program to calculate smallest number with permutations divisible by a set of numbers

(EDIT: here is the follow up question) I have written a small program in C to calculate the smallest number where any of its permutations or the number itself is divisible by a set of given numbers. ...
1
vote
2answers
101 views

Number to german decimal format converter function [closed]

I have a function that formats a number (even a float) to a German decimal format. I got this function from here ...
4
votes
2answers
1k views

Hexadecimal number to decimal conversion

I am a semi-beginner in C++ and I have a project in C++ to convert a hexadecimal integer into decimal equivalent, but I extended it and now this program can also convert a fractional part. Logic I ...
3
votes
0answers
68 views

Recursive factorial calculations in Rust

I am trying to calculate very large factorials. I am looking to speed it up as 10000! takes approximately a minute and a half. ...
6
votes
1answer
405 views

C++ console program

I have been learning C++ programming. What you see here is all that I know how to do at this point. I look forward to learning more and I know there are better ways to accomplish a task such as ...
7
votes
4answers
1k views
6
votes
2answers
278 views

Reverse binary representation of an int (only significant bits)

This based on this question in StackOverflow. The accepted answer uses Convert.ToString(int, base) to get the binary string, ...
2
votes
2answers
48 views

K&R atoi() variation

I'm currently learning C with The C Programming Language by K&R and this is my current exercise: Rewrite appropriate programs from earlier chapters and exercises with pointers instead of array ...
3
votes
2answers
100 views

C - K&R getint() variation

I'm currently learning C with "The C Programming Language" by K&R. At the moment I'm at the chapter about pointers (since I come from Java, they are new to me). In the book is an example code for ...
8
votes
1answer
187 views

Tuple<int, int> replacement

I use the following structure in a web service where performance is critical. It is used for making joins between domain data objects, the key is made of two integers. The idea is to fit the two 32 ...
8
votes
2answers
262 views

Simple function to verify if a number is integer

Sometimes, there's the need to verify if a given number is an integer or a decimal. Since JavaScript doesn't distinguish between both, I've made an extremelly basic function. ...
5
votes
2answers
100 views

Add two numbers stored as a list in F#

I am solving the following problem: You are given two lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the ...
5
votes
3answers
675 views

Function that adds two integer strings

I wrote this method that adds two integers in the form of strings together. This way I can add large integers without overflowing. How efficient is the code that I wrote? I am by no means a great ...
12
votes
3answers
991 views

Safe multiplication of two 64-bit signed integers

The function below implements safe multiplication of two 64-bit signed integers, preventing overflow from occurring: ...
2
votes
3answers
94 views

Method that returns an integer chosen by user

Can I make this: if (oneFour == 1 || oneFour == 2 || oneFour == 3 || oneFour == 4) shorter, especially if I'm gonna need a wider range of integers? Do I need to ...
5
votes
3answers
2k views

Counting words, letters, average word length, and letter frequency

I'm pretty sure my code is mostly correct. I think I'm having formatting errors more than anything. I keep receiving warnings about "double to float and int to float,possible loss of data. Here is ...
10
votes
2answers
910 views

Convert Persian digits to English numbers

I use the following code to convert ۱۲۳۴۵ to ‍12345, effectively transliterating the persian numbers into latin numbers: ...
7
votes
1answer
113 views

IntModulus long addition and subtraction

One of the remarks in this answer to my question concerning IntModulus says What's more problematic is that you don't have matching argument symmetry for add ...
6
votes
2answers
106 views

IntModulus reloaded

As my question Modular arithmetic was hard to review and terribly long, I've added a few comments to the easier part, namely IntModulus. The code uses Guava and ...
13
votes
2answers
249 views

Modular arithmetic

As the name says, LongModulus is a pretty long (lengthy) class implementing modular arithmetic for a long modulus. As overflow ...
5
votes
3answers
211 views

K&R 4-12 recursive converter int to string

The exercise is: Adapt the ideas of printd to write a recursive version of itoa; that is, convert an integer into a string by calling a recursive routine. I wonder if I have correctly ...
4
votes
2answers
74 views

Test if arithmetic operation will cause undefined behavior

I've written a command line calculator as an exercise to get ready for my upcoming first programming job. The whole program source is around 450 lines of code, which I think is too long for a single ...
1
vote
0answers
51 views

Big Integers and parallel execution with OpenMP

This is part of an implementation of Rabin-Williams signatures as described by Bernstein in Section 6 of "RSA signatures and Rabin–Williams signatures: the state of the art" using Tweaked Roots. The ...
6
votes
1answer
401 views

Multiplying and adding big numbers represented with strings

I got a very unusual problem of adding and multiplying very big numbers (≥ 1e+100). So I've written simple functions that would operate on string representations of numbers, both as an input and an ...
5
votes
1answer
128 views

Saturated arithmetic

For project Euler, I need quite often to test things like is x*y*z < 1e18. Since BigInteger is usually too slow, ...
3
votes
2answers
129 views

Mystery sum with placeholder digits

I came across this coding problem. Back in primary school, maybe you were sometimes asked to solve a fill-in-the-blank sum - or "mystery sum" - in which certain digits are removed and you had ...