Why is Int32's maximum value 0x7FFFFFFF?

c# types int32
Afshin Mehrabani picture Afshin Mehrabani · Nov 5, 2012 · Viewed 44.7k times · Source

I saw in MSDN documents that the maximum value of Int32 is 2,147,483,647, hexadecimal 0x7FFFFFFF.

I think, if it's Int32 it should store 32-bit integer values that finally should be 4,294,967,295 and hexadecimal 0xFFFFFFFF.

My question is why Int32 stores 31-bit integer values?

Answer

Lloyd picture Lloyd · Nov 5, 2012

It's because it's a signed integer. An unsigned 32-bit integer give you the value you expect.

Check out this MSDN page - http://msdn.microsoft.com/en-us/library/exx3b86w(v=vs.80).aspx

For a more in depth explanation on why this is check out the link in Jackson Popes answer related to Two's Complement number representation.

Also some further reading.

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