CODEWITHSUNDEEP
javascriptc#uint
Ghaith Sabbagh
Ghaith Sabbagh

Reputation: 63

I can't get proper uint32 number in javascript

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.

Upvotes: 1

Views: 4292

Answers (3)

Derviş Kayımbaşıoğlu
Derviş Kayımbaşıoğlu

Reputation: 30585

You cannot convert 431430059159441001 to unsigned integer in . 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)

Upvotes: 1

Tamas Hegedus
Tamas Hegedus

Reputation: 29926

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 BigInts. 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

Upvotes: 5

Jonas Wilms
Jonas Wilms

Reputation: 138307

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)

Upvotes: 1

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