I can't get proper uint32 number in javascript

Question

i am trying to convert a long number to unit in JavaScript, but the result i got it different from the one i already have in c#.

c#:

var tt=431430059159441001;
var t=(UInt32)tt;//1570754153

js:

var arr =new Uint32Array(1);
arr[0]=431430059159441001;//1570754176

so could any body explain why there is difference.

Answer 1

That's because your number literal is rather a 64 bit integer, and that cannot be represented in JavaScripts regular Number type. The number type is a 64-bit precision floating point number, which can only represent integer values up to around 2**53 . So I would recommend to just not use such a huge number literal.

A recent development in the JavaScript world is BigInt s. If you can afford to use them, then your code is easy to fix:

 var t = Number(BigInt.asUintN(32, 431430059159441001n)); console.log(t); // 1570754153 

Answer 2

This is not about uints, but about floats. JavaScript uses floating point numbers, and your number exceeds the maximum range of integers that can safely be represented:

console.log(431430059159441001)

Answer 3

You cannot convert 431430059159441001 to unsigned integer in c# . Max Value of UInt32 is 4294967295 . So the var t=(UInt32)431430059159441001; assignment gives Compiler error.

also 431430059159441001 is larger then max value of float number (javascript holds number with float format)