biginteger | 易学教程

Extremely large numbers in javascript

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问题 I\'m working on the Project Euler problems (currently question 13). For this question I have to find the first 10 digits of the sum of 100 numbers all of a size similar to this: 91,942,213,363,574,161,572,522,430,563,301,811,072,406,154,908,250 I think I could use something like Java\'s BigInteger, but I started solving the problems in JavaScript (I\'m trying to boost my js abilities for work), and I would like to continue using it, even to solve this problem. I\'d like to stick to pure JS if

JSON transfer of bigint: 12000000000002539 is converted to 12000000000002540?

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问题 I\'m transferring raw data like [{id: 12000000000002539, Name: \"Some Name\"}] and I\'m getting the object [{id: 12000000000002540, Name: \"Some Name\"}] after parsing, for now server side converting id into string seems to help. But is there a better way to transfer bigint data correctly? 回答1: The value is actually not exceeding the maximum numeric value in JavaScript (which is "only" 1.7 308 or so). However, the value is exceeding the range of "integral precision". It is not that the wrong

What does BigInteger having no limit mean?

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问题 I looked into this stackoverflow question relating to Big Integer and specifically I do not understand this line (the words in italics): In the BigInteger class, I have no limits and there are some helpful functions there but it is pretty depressing to convert your beautiful code to work with the BigInteger class, specially when primitive operators don\'t work there and you must use functions from this class. I don\'t know what I am missing but to represent something that has no limit you

Handling large numbers in C++?

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What is the best way to handle large numeric inputs in C++ (for example 10^100 )? For algorithms I usually switch over to ruby and I sometimes use strings. Any other good methods? hometoast It sounds like you're looking for a way to enter Arbitrary Precision numbers. here are two libraries you could use: GMP and MAPM Check out The Large Integer Case Study in C++.pdf by Owen Astrachan. I found this file extremely useful with detail introduction and code implementation. It doesn't use any 3rd-party library. I have used this to handle huge numbers (as long as you have enough memory to store

The best cross platform (portable) arbitrary precision math library [closed]

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问题 I\'m looking for a good arbitrary precision math library in C or C++. Could you please give me some advices / suggestions? The primary requirements: It MUST handle arbitrarily big integers (my primary interest is on integers). In case that you don\'t know what the word arbitrarily big means, imagine something like 100000! (the factorial of 100000). The precision MUST NOT NEED to be specified during library initialization / object creation. The precision should ONLY be constrained by the

How to generate a random BigInteger value in Java?

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问题 I need to generate arbitrarily large random integers in the range 0 (inclusive) to n (exclusive). My initial thought was to call nextDouble and multiply by n, but once n gets to be larger than 2 53 , the results would no longer be uniformly distributed. BigInteger has the following constructor available: public BigInteger(int numBits, Random rnd) Constructs a randomly generated BigInteger, uniformly distributed over the range 0 to (2 numBits - 1), inclusive. How can this be used to get a

How to use BigInteger?

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问题 I have this piece of code, which is not working: BigInteger sum = BigInteger.valueOf(0); for(int i = 2; i < 5000; i++) { if (isPrim(i)) { sum.add(BigInteger.valueOf(i)); } } The sum variable is always 0. What am I doing wrong? 回答1: BigInteger is immutable. The javadocs states that add() "[r]eturns a BigInteger whose value is (this + val)." Therefore, you can't change sum , you need to reassign the result of the add method to sum variable. sum = sum.add(BigInteger.valueOf(i)); 回答2: sum = sum

Big integers in C#

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问题 Currently I am borrowing java.math.BigInteger from the J# libraries as described here. Having never used a library for working with large integers before, this seems slow, on the order of 10 times slower, even for ulong length numbers. Does anyone have any better (preferably free) libraries, or is this level of performance normal? 回答1: As of .NET 4.0 you can use the System.Numerics.BigInteger class. See documentation here: http://msdn.microsoft.com/en-us/library/system.numerics.biginteger(v

Handling large numbers in C++?

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问题 What is the best way to handle large numeric inputs in C++ (for example 10^100 )? For algorithms I usually switch over to ruby and I sometimes use strings. Any other good methods? 回答1: It sounds like you're looking for a way to enter Arbitrary Precision numbers. here are two libraries you could use: GMP and MAPM 回答2: Check out The Large Integer Case Study in C++.pdf by Owen Astrachan. I found this file extremely useful with detail introduction and code implementation. It doesn't use any 3rd

Arbitrary-precision arithmetic Explanation

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问题 I\'m trying to learn C and have come across the inability to work with REALLY big numbers (i.e., 100 digits, 1000 digits, etc.). I am aware that there exist libraries to do this, but I want to attempt to implement it myself. I just want to know if anyone has or can provide a very detailed, dumbed down explanation of arbitrary-precision arithmetic. 回答1: It's all a matter of adequate storage and algorithms to treat numbers as smaller parts. Let's assume you have a compiler in which an int can