Conversion from unsigned int to float

Question

warning C4244: '=' : conversion from 'unsigned int' to 'float', possible loss of data  

Shouldn't a float be able to handle any value from an int?

unsigned int: 0 to 4,294,967,295  
float 3.4E +/- 38 (7 digits) 

Wiki:

The advantage of floating-point representation over fixed-point (and

integer) representation is that it can support a much wider range of values.

Any insight would be helpful, thanks.

http://msdn.microsoft.com/en-us/library/s3f49ktz%28VS.80%29.aspx

Answer 1

'unsigned int' and 'float' both use 32 bits to store values. Since a float has a larger range, it necessarily sacrifices some precision. This means that there are some unsigned int values that cannot be accurately represented in a float. MSDN provides some more details.

Answer 2

While float supports a wider range of values than unsigned int, it does so with less accuracy. Floats have a 23-bit mantissa which, as you posted, is only about 7 decimal digits. unsigned ints support over 9 decimal digits.

Suggestion: use double, not float.

Edit: Actually, I retract that suggestion; floating-point and integer data types are fundamentally different and are not directly convertible. What integer value do you expect to get for Single.MaxValue? For Single.NegativeInfinity? Explaining why you want to convert from float to int would be helpful.