long-integer

If you try to run the following code public class Main { public static void main(String[] args) { long a = (long)Math.pow(13, 15); System.out.println(a + " " + a%13); } } You will get "51185893014090752 8" The correct value of 13^15 is 51185893014090757 , i.e. greater than the result returned by Math.pow by 5 . Any ideas of what may cause it? You've exceeded the number of significant digits available (~15 to 16) in double-precision floating-point values. Once you do that, you can't expect the least significant digit(s) of your result to actually be meaningful/precise. If you need arbitrarily

I was working on an embedded project when I ran into something which I thought was strange behaviour. I managed to reproduce it on codepad (see below) to confirm, but don't have any other C compilers on my machine to try it on them. Scenario: I have a #define for the most negative value a 32-bit integer can hold, and then I try to use this to compare with a floating point value as shown below: #define INT32_MIN (-2147483648L) void main() { float myNumber = 0.0f; if(myNumber > INT32_MIN) { printf("Everything is OK"); } else { printf("The universe is broken!!"); } } Codepad link: http://codepad

I'm doing a program that aproximate PI and i'm trying to use long long, but it isn't working. Here is the code #include<stdio.h> #include<math.h> typedef long long num; main(){ num pi; pi=0; num e, n; scanf("%d", &n); for(e=0; 1;e++){ pi += ((pow((-1.0),e))/(2.0*e+1.0)); if(e%n==0) printf("%15lld -> %1.16lld\n",e, 4*pi); //printf("%lld\n",4*pi); } } karadoc %lld is the standard C99 way, but that doesn't work on the compiler that I'm using (mingw32-gcc v4.6.0). The way to do it on this compiler is: %I64d So try this: if(e%n==0)printf("%15I64d -> %1.16I64d\n",e, 4*pi); and scanf("%I64d", &n);

I'm working on a programming language, and today I got the point where I could compile the factorial function(recursive), however due to the maximum size of an integer the largest I can get is factorial(12). What are some techniques for handling integers of an arbitrary maximum size. The language currently works by translating code to C++. If you need larger than 32-bits you could consider using 64-bit integers (long long), or use or write an arbitrary precision math library, e.g. GNU MP . If you want to roll your own arbitrary precision library, see Knuth's Seminumerical Algorithms, volume 2

How can I generate random Int64 and UInt64 values using the Random class in C#? Noldorin This should do the trick. (It's an extension method so that you can call it just as you call the normal Next or NextDouble methods on a Random object). public static Int64 NextInt64(this Random rnd) { var buffer = new byte[sizeof(Int64)]; rnd.NextBytes(buffer); return BitConverter.ToInt64(buffer, 0); } Just replace Int64 with UInt64 everywhere if you want unsigned integers instead and all should work fine. Note: Since no context was provided regarding security or the desired randomness of the generated

How can I change the (default) type for ActiveRecord's IDs? int is not long enough, I would prefer long. I was surprised that there is no :long for the migrations - does one just use some decimal? Credits to http://moeffju.net/blog/using-bigint-columns-in-rails-migrations class CreateDemo < ActiveRecord::Migration def self.up create_table :demo, :id => false do |t| t.integer :id, :limit => 8 end end end See the option :id => false which disables the automatic creation of the id field The t.integer :id, :limit => 8 line will produce a 64 bit integer field To set the default primary key column

I keep finding both on here and Google people having troubles going from long to int and not the other way around. Yet I'm sure I'm not the only one that has run into this scenario before going from int to Long . The only other answers I've found were "Just set it as Long in the first place" which really doesn't address the question. I initially tried casting but I get a " Cannot cast from int to Long " for (int i = 0; i < myArrayList.size(); ++i ) { content = new Content(); content.setDescription(myArrayList.get(i)); content.setSequence((Long) i); session.save(content); } As you can imagine I