Questions tagged [integer]

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
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1answer
399 views

Digit Summing Function

I'm working through the common divisibility tests, and implementing them in Racket. I'm working on divisible by three, for which I thought it'd be nice to keep summing until I got to a single digit (...
5
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4answers
3k views

Squaring an integer by repetitive addition

I've written two functions: is_integer(), which tries to get a positive or a negative integer as input and returns the same value. ...
2
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2answers
95 views

Writing an API for checked subtraction

I have to write an API for checked subtraction where the input minuend can be < 0 but subtrahend can't be < 0. I think I've covered all the cases of underflow and overflow. With given conditions ...
5
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5answers
3k views

Swapping two integer numbers with no temporary variable

I tried to swap 2 integer numbers without using an additional variable as a traditional swap. Is it legal in C++? My VC compiler doesn't complain nor gives any warning about it. If so, how can I ...
3
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1answer
77 views

Fast power in Go

I just started learning Go. To start playing with it, I've implemented the fast power algorithm: Any suggestions or criticisms regarding the coding style? ...
3
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2answers
268 views

BigRational based on BigIntegers

For Project Euler I've implemented a BigRational. The functionality is rather limited, just things I needed or will probably need soon. The style departs a bit from ...
15
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1answer
2k views

Multiplication 128 x 64 bits

I was fooling around with the Collatz sequence a bit and found out that long is only sufficient for starting values below ...
4
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3answers
698 views

Listing the representations of integer M as a sum of three squares M = x^2 + y^2 + z^2

I am trying a number as the sum of 3 squares. For my particular project I will require a complete list since the next step is to compute nearest neighbors (here). In any case we'd like to find \$ M =...
6
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4answers
1k views

Sum of digits in a^b

I'm trying to calculate a problem which requires sum of digits in \$a^b\$, where \$0 \le a \le 9\$ and \$0 \le b \le 4000\$. I have seen various other posts similar to this, but I haven't acquired ...
12
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2answers
204 views

UIntArray class in PHP (part 2)

This question is the follow up of the question: UIntArray class in PHP @Brythan provided a really nice review and I have improved my class. I have addressed almost all the issues he pointed out (...
12
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3answers
6k views

Random permutation of int[] and ArrayList<Integer>

I wrote a simple program using int[] and ArrayList<Integer> which aims to get a random permutation output between 1 to 10, ...
3
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4answers
1k views

Function to extract bytes as a decimal

You give this function a pointer and how many bytes you want to extract as a decimal and it returns it. ...
11
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4answers
4k views

Computing the square root of a 64-bit integer

When sieving primes up to some 64-bit number n I need to determine an upper bound for the greatest potential factor of n, which ...
11
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1answer
184 views

UIntArray class in PHP

I have seen UInts being natively supported in other languages. PHP allows you to install a third party extension, but I can't do that ATM, so I've decided to create ...
8
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4answers
3k views

Computing factorials

I am computing factorials as part of teaching myself C++. I am looking for feedback on efficiency, style and any bad practices I may be using. ...
6
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2answers
92 views

Finding the Greatest Integer and Ties

I'm trying to find the greatest integer of four integers and its ties. I used the following code. Is there anyway to simplify this? ...
11
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2answers
4k views

Mostly portable 128 by 64 bit division

I wrote this out of curiosity. It is based on the theory behind Knuth's Algorithm D and is intended to emulate the behavior of the x86 div instruction (though the ...
10
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3answers
781 views

Beginnings of a base-conversion game in Python

I'm pretty very new to python, so I thought that I'd write a game to teach me python and better teach me how to think in hexadecimal and binary. I'm starting off by writing a few functions to convert ...
10
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2answers
2k views

Parsing integers safely

Background I'm writing user input validation for a client-side JavaScript web application. Users enter numerals representing an integer into an <input>. As ...
10
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2answers
453 views

Lossy packing 32 bit integer to 16 bit

I am working on the lossy 16 bit representation for 32 bit integers that catches all 32 bit range with precision depending on absolute value. My idea is to store integer ...
5
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4answers
271 views

C library that converts integers to string and vice-versa

I've created this little library to help ease myself (and for others, hopefully) with the pain of having to convert integers to string and vice-versa. It's written in C, and for maximum portability I ...
2
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1answer
2k views

Encoding and decoding exercise

I was issued the following coding challenge from a company to write an encoding and decoding function: Encoding: This function needs to accept a signed integer in the 14-bit range [-8192..+8191] ...
3
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2answers
1k views

Emulating __uint128_t

I developed a lot of code locally with __uint128_t only to find out that it is not available on the target platform. I am now trying to write my own struct that ...
1
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2answers
281 views

Bignum library with arbitrary bases

I just started development on a new bignum library that can operate on numbers of any arbitrary base (up to 232). I want to get a good idea of where I can improve before taking things any further. ...
43
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5answers
34k views

Incrementing Integers in Map

I have a HashMap<Token, Integer>, which counts occurrences of Token. Each time Token ...
6
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2answers
2k views

Why are these functions slower than BigInteger's included methods?

I tried writing alternative functions to Java's BigInteger.add(BigInteger.ONE), BigInteger.add(BigInteger), and ...
2
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1answer
7k views

Tough List Comprehension Split Letters and Numbers

So, another challenge from my professor. I've finished it, but wanted to get some feedback, and see how other people might work this problem. Assume you have a string, such as "Hello 34215 World ...
13
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1answer
8k views

Thread-Safe Integer Sequence

I would like to give an Integer to whatever demands it. For that I use the following code ...
3
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2answers
485 views

Function for splitting an integer into smaller values

This is the function I've implemented in an answer to this question. I've tried to make this as simple and idiomatic as possible, using C++11. Could this still be improved in any way? ...
6
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1answer
77 views

Converting the integers to their equivalent string representations

I have the following function which converts an integer (such as 103) to its string representation ("one hundred three"): ...
2
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2answers
3k views

Two solutions with min max values - which should be slower?

While practicing at codinbat.com on the assignment: Given an array length 1 or more of ints, return the difference between the largest and smallest values in the ...
2
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1answer
2k views

Write int, short int or any integer value in a file in binary form using fputc

I am trying to write binary values in a file using fputc. In my case it is a short int. The file must be opened in "w" mode. I'...
9
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3answers
49k views

Converting an integer to binary, hex, and octal

I've started caring about standards and the beauty of my code. I doubt whether I've written it correctly and aesthetically. Can you please judge this simple, exemplary program? I want to know of any ...
5
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3answers
24k views

Printing every digit of a number

Which of these three methods is better? ...
4
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2answers
196 views

Rounding ints division result to certain “granularity”

In my program I call "granularity" the "minimum step" for a number. For example, if granularity == 4 then I only work with numbers "0, 4, 8, 12 etc" (so normal <...
11
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2answers
13k views

Division without / operator

I created a method that does division without the / operator. I believe this code is a bit slow and can be improved, but I am not sure how to do so. I'm not so good ...
4
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2answers
411 views

fractions data type — when to reduce? [closed]

Here is my Python implementation of a simple fractions class: ...
8
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2answers
753 views

Container for list of ranges

I made a C++ container of an ordered list of integers, that, in order to save space, I save as ranges: For example, the list \$ \{1,2,3,5,6,7,8,9,20\} \$ is saved in memory as \$ \{(1,3), (5,9), (20,...
6
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3answers
2k views

Optimizing unique partitions of integers

I am working on a project involving the unique partitioning of integers. I.e. I am looking to have all of the partitions of n = x1 + x2 + x3 + ... + xk, where xi = xj implies i = j. For example, if I ...
12
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5answers
15k views

Implementation of atoi()

I implemented the atoi() function! Here is my code: ...
4
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3answers
10k views

Checking endianness at compile-time

I've tried to make a portable way of ensuring endian-specific code gets generated at compile time using C++11, however I only have a computer with Windows on it to test at the moment. Because of this, ...
7
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2answers
6k views

Int stack implementation

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18
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4answers
31k views

Displaying each number of an integer in a sequence

One of the books I'm currently reading to learn C# asked me to write a method that takes an integer between 1 and 99999 and displays each number in that integer in a sequence, separating each digit by ...
5
votes
1answer
574 views

Conversion from decimal to negabinary and vice versa in Haskell

Recently I set about to writing conversion functions in Haskell between decimal and negabinary. I tried to write them in as much functional a style as possible, also aiming at brevity. Below I present ...
5
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2answers
132 views

What might be another way to test if int is 32 bits wide at compile time?

Below is code that will compile when INT_MAX is equal to 232. It will generate a compiler error when INT_MAX is not equal to 232....
5
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3answers
2k views

Number to words problem

This is a very long solution I've been working on to a Number to Words problem. I've identified that there's a lot of repeating logic (e.g. 'if writing > 0', 'writing = integer /',). How would you ...
2
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1answer
100 views

Check robustness of function to add an interval to a date

Background of the problem My Class level variables: ...
26
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4answers
49k views

Counting number of 1's and 0's from integer with bitwise operation

Is there a better way of doing this? ...
26
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4answers
60k views

Simple method to detect int overflow

To detect int overflow/underflow in C, I use this code. What might be a simpler and more portable way of coding this (that is, fewer conditions)? Assume 2's ...
4
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1answer
11k views

Writing integer to binary file

I wrote a python function that writes a integer to a file in binary form. But are there any ways that I can reduce the number of steps, is there a more efficient way to write a integer to a file? <...

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