# 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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### Long arithmetic addition in JS

The implementation of the algorithm which adds two number in string form with arithmetic rules. ...
1k 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 ...
5k 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? ...
5k 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 ...
168 views

### Text representation for numbers with python

Simple function which returns a text representation for numbers in range [1...1000]. ...
8k 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. ...
2k 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 ...
294 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 ...
3k 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: ...
28k 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? ...
86 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. ...
6k 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 https://stackoverflow.com/questions/149055/how-can-i-format-numbers-as-money-in-...
14k 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 ...
710 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. ...
552 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 ...
7k views

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### 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, ...
179 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 ...
1k 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 ...
1k 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 ...
4k views

### Character to decimal conversion

This converts from character representation of integers to their decimal value: ...
7k 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. ...
679 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 two ...
2k 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 ...
6k 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: ...
99 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 ...
20k 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 ...
14k 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: ...
899 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 and ...
122 views

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 ...
795 views

### Modular arithmetic

As the name says, LongModulus is a pretty long (lengthy) class implementing modular arithmetic for a long modulus. As overflow ...
401 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 answered ...
212 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 ...
7k 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 ...
756 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, ...
332 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 ...
90 views

I made a bigint class that can add unsigned unlimited precision integers by splitting number into chunks less than 9999, and if a part is bigger than 9999 I take mod 10000 and carry 1 to the next part....
1k views

### HackerEarth Girlfriend's Demand challenge, solved two ways

I solved the Girlfriend's Demand challenge on HackerEarth. In summary: Input: First line of the input contains a string S. Next line contains an integer Q, the number of queries. Each of the next ...
368 views

### Mockup in C of hardware implementation for multiplication of signed integers

I challenged myself to implement multiplication of signed integers using only +, -, >>,...
596 views

### Having fun with JNI: formatting a number

I attempted some (easy) coding with Java Native Interface. This is what I have: six_pack_Neatifier.h: (autogenerated by javah) ...
565 views

### SPOJ problem - The last digit of a number to a power

Here is the problem statement: Given integers $a$ ($0 \le a \le 20$) and $b$ ($0 \le b \le 2,147,483,000$), where $a$ and $b$ are not both 0, find the last digit of $a^b$. ...
8k views

### Bills and coin denomination program

I am currently in an intro C++ programming class. We have an assignment where we have to convert a dollar and cents amount, say \$192.89, to bills and coins using the least amount of both. Below is the ...
355 views

### Fastest sum of absolute values of 32 differences

A long should be treated as a list of 32 unsigned numbers, each of them just two bit long. So 0x1234F... represents ...
167 views

### Given bit strings, perform a bitwise addition

I'm looking for code-review, optimizations and best practices. This code is a Java adaptation of code on geeksforgeeks.org. Please verify if space complexity is $O(n)$ where n is number of bits, and ...
458 views

### Truncating integer using string manipulation

I have a class with a data member that needs to be rounded up to a 2 digit integer, irrespective of the number of the input digits. For example: ...
18k views

### Conversion functions between binary, hexadecimal and ASCII

I've written a small suite to easily convert my data between binary, hexadecimal and ASCII: ...
3k views

### Performing several integer division operations on an array

Program: Given an array A of size N. Given Q operations, each operation contains an integer D. In each operation you have to divide all the elements of the array by D. For example, for ...
792 views

### atoi implementation in C

I'm looking for feedback on my atoi implementation here in C. Any feedback would great. I made my own atoi for fun and to learn ...
I'm trying to develop a simple program to evaluate integral powers of a complex number $z$ , that is, $z^n$, where $z$ is in the algebrical form $a+i b$ and $n \in \mathbb{Z} ^{*} _{+}$. ...