Thread: How accurate is the following...

Originally Posted by filker0

When I compile and run this (on a mac-mini, though that doesn't really matter) I get the following:

Code:

MiniMac:~ filker0$ cc -o float float.c
MiniMac:~ filker0$ ./float 
2/3 as float: 0.666666686534882, double: 0.666666666666667

The header file /usr/include/float.h (or wherever your compiler puts its standard header files) contains the various limits for the various floating point representations supported by your compiler.

Although amusingly enough, you have just proved their statement to be true. The double in this case gives you just about twice as many points of accurate precision. Watch:
0.666666686534882 .. seven accurate positions.
0.666666666666667 .. fifteen accurate positions.

Funny, that.

[edit]
If you want to include the preceeding zero, you end up with exactly twice as many points of accuracy. 8 and 16 respectively. So for teaching purposes, yeah, it's a pretty accurate statement.
[/edit]


Quzah.