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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2
votes
2answers
33 views

Dividing a long (arbitrary-precision) number by an integer

As part of a (slightly) larger program, I needed to write a function that could take an arbitrarily large number and divide it by a small number. In this program, I will be dividing this number ...
0
votes
1answer
21 views

Convert NSInteger into NSString

This is my sample code to convert a integer into string. Is it very costly to do the multiple loops of [NSMutableString stringWithFormat:..]? I.e should I just use appendString and get the NSString ...
5
votes
2answers
319 views

itoa base function in C

This is a function that converts an integer value to a null-terminated string using the specified base and stores the result in a char array that I must allocate (...
2
votes
1answer
33 views

Avoiding “warning: Use of uninitialized value” when fetching an integer CGI parameter

I was using this code to fetch a CGI parameter: $page = int(param('page')); This sometimes results in: ...
4
votes
1answer
44 views

Normalize integer types to float range

I wrote two template functions to take an integer type and output a float in the given range. One function takes signed integers and the other takes unsigned ...
3
votes
2answers
60 views

Merge and sorting arrays of String and int in more efficient methods

Are there better methods for merge and sorting arrays of int and String in more efficient methods both time-complexity wise and ...
3
votes
1answer
53 views

Handling GetTickCount() overflow in timeouts

This is code which must run on XP, so no GetTickCount64, and which should correctly handle the value wrapping around after 49 days. Can it be improved? ...
4
votes
1answer
46 views

LEB128 in Haskell

I have implemented the LEB128 encoding for unsigned integers. I'm fairly new to Haskell so I have some doubt about the coding style I'm using, particularly the definition of ...
8
votes
1answer
99 views

Portable safe unsigned integer arithmetic

tl;dr The purpose of the code is to allow writing ...
2
votes
2answers
73 views

Calculating the sum of the digits in 2^1000

I have a program which calculates the sum of the digits in the number 21000. The program is not beautiful and I was hoping for some advice on how to improve it. The idea I have used is to create an ...
2
votes
1answer
63 views

String-casting utility functions

I wrote a small header that is supposed to take care of calling the right strtoX or or stoX function for me and doing so at ...
5
votes
1answer
56 views

`read` re-implemented for Int's

I have written a safe read function for haskell (for education!). I think this is fairly idiomatic haskell code, but I'd like to know for sure. If you see anything else that could be improved, please ...
3
votes
2answers
256 views

Get number from N

I'm trying to find the shortest and best way to achieve the following: Given input integer $N, get the following output: n = 0, output = 0 n = 1, output = 0 n = 2, output = 10 n = 3, output = ...
8
votes
1answer
94 views

Corrupting Java arithmetic through reflection

Inspired by a PPCG answer, I wrote this code, which shuffles the autoboxing caches of Number subclasses. This leads to, among other things, outputting ...
3
votes
1answer
49 views

Comparing a string that can hold a numeric value

I am refactoring a part of big old system developed in Java. I came across a situation where we are migrating some data types, and there will be use of both types. For compatibility, as all the old ...
6
votes
1answer
94 views

Large integer class for storing integer data as a char array

I am working on a LargeInteger class to store Integers beyond the size of long long as a dynamic character array. I have ...
2
votes
1answer
155 views

Simple calculation program in assembly MASM

I am a beginner in assembly. This program calculates: (Z+Z)+(X-Y) ...
1
vote
2answers
78 views

Concatenate three 16-bit integers in one 64-bit integer with C++

I am looking for an elegant alternative of the following code where wordXX contains always 16 bits: ...
7
votes
2answers
63 views

Portable byte order conversion

I'm trying to improve the portability of a file format converter, specifically to POSIX platforms other than Linux. I'd appreciate a review of the following functions used for converting between ...
2
votes
2answers
75 views

Python combine two integers to a third

We have three integers: A, B, C where the first (i.e. the most significant) digit of C is the first digit of A, the second digit of C is the first digit of B, the third digit of C is the second ...
5
votes
1answer
79 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
0answers
60 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
54 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: ...
11
votes
4answers
1k 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
62 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
629 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: ...
12
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 ...
17
votes
2answers
364 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
47 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
126 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 everything else, but I'm not too familiar with C++ code, and and am trying to figure out how to make ...
11
votes
2answers
204 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
126 views

Implementing min of 3 numbers in Mic-1 code

I have the following algorithm to find a minimum of three input numbers: ...
4
votes
2answers
560 views

Java conversion of base 16 to base 64

I wrote a solution in Java to solve the problem here. I use BigInteger to convert first from base 16 to base 10, then base 10 to base 64. This seems quite ...
7
votes
2answers
138 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
403 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
147 views

Long arithmetic addition in JS

The implementation of the algorithm which adds two number in string form with arithmetic rules. ...
5
votes
1answer
51 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
165 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
2k 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 ...
2
votes
1answer
57 views

Text representation for numbers with python

Simple function which returns a text representation for numbers in range [1...1000]. ...
11
votes
7answers
661 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
940 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
258 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
494 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: ...
19
votes
10answers
6k 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
55 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
377 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 http://stackoverflow.com/questions/149055/how-can-i-format-numbers-as-money-in-...
4
votes
2answers
4k 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
122 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
447 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 ...