An unsigned integer, or uint, is a numeric datatype that only can hold positive integers. Like it’s name suggests, it represents an unsigned 32-bit integer. The uint keyword itself is an alias for the Common Type System type
System.UInt32. This datatype is present in
mscorlib.dll, which is implicitly referenced by every C# project when you create them. It occupies four bytes of memory space.
Unsigned integers can hold any value from 0 to 4,294,967,295.
Examples on how and now not to declare unsigned integers
uint i = 425697; // Valid expression, explicitly stated to compiler var i1 = 789247U; // Valid expression, suffix allows compiler to determine datatype uint x = 3.0; // Error, there is no implicit conversion