Thread: weird problem!

i have a very weird problem with a float.
i've read from a file a number:

423.230000

if i:

Code:

printf("%f ",tmp[*n].val+x);

it prints me:
423.230000 that is ok!
tmp[*n].val is a float component of a structure containing the integer (423.00000) and x is a float containing 0.230000

but if i do:

Code:

tmp[*n].val+=x;
printf("%f ",tmp[*n].val);

it prints me:
423.230011
Where does the 0.000011 comes from ?
This problem occurs within a function!

How can I fix it ?

Thank you!