# 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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### 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: ...
24k 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 ...
684 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. ...
551 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 ...
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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, ...
166 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 ...
3k views

### Character to decimal conversion

This converts from character representation of integers to their decimal value: ...
6k 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. ...
628 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 ...
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### Safe multiplication of two 64-bit signed integers

The function below implements safe multiplication of two 64-bit signed integers, preventing overflow from occurring: ...
98 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 ...
19k 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 ...
12k 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: ...
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### 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 ...
780 views

### Modular arithmetic

As the name says, LongModulus is a pretty long (lengthy) class implementing modular arithmetic for a long modulus. As overflow ...
390 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 ...
191 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 ...
700 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, ...
326 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 ...
83 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....
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### 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 +, -, >>,...
587 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) ...
513 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 $a^b$. ...
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### 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 ...
351 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 ...
156 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: ...
17k 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 ...
768 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 ...
322 views

### Keeping integer addition within bounds

I have to read a int8_t from a buffer, read a uint8_t from the camera's current settings, add them together, keep new value ...
1k views

### Program to evaluate powers of complex numbers

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 $n \in \mathbb{Z} ^{*} _{+}$. ...
546 views

### Distinguishing user input numbers and characters

I am currently taking a computer science class in high school, and it is my first time programming (2 weeks since I started). I have currently finished my program; however, there were a few details ...
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### Pollard p - 1 implementation

I'm trying to implement the Pollard p - 1 algorithm seen here, in Java. It has a C implementation here. I am using it for numbers without any smaller factors so trial factorisation isn't needed. My ...
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### Network byte order to host byte order

While doing a little project involving sniffing packets, I found myself programming a cross platform network to host byte order and host to network byte order, this is my first time developing a ...
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### Integers from scratch in Haskell

Inspired by this article about natural numbers from first principles in swift I implemented integers from scratch in Haskell. Besides obviously being extremely inefficient, is this code idiomatic ...
334 views

### Parsing a long without using inbuilt function parseLong

I came across it as a problem to solve. What kind of limitations are there? ...
719 views

### Partition a list of numbers into even and uneven numbers

Input: An array of integers. Output: That same array, but with the even numbers at the front and the uneven numbers at the back of the array. I wrote three different solutions, depending on the ...