Strange Variable assignment - need translation

I'm trying to decipher this C code and translate it into PHP (long
story). Can anyone help?

(xx is a float being passed into the function)


temp = (x = xx - 1.0) + 5.5;
temp = (x + 0.5) * log(temp) - temp;



My assumption was this:
x = xx - 1.0
temp = x + 5.5
then later, temp = (x + 0.5) * log(temp) - temp

For some reason, I don't think my assumption is correct as the wrong
values are coming out of the function. The weird use of parentheses/
assignment operators is throwing me off.

Is there a different (a.k.a. more verbose) way to write that snippet?
I want to make sure I get this right.

Thanks,

Jon

You seem to have it correct, slightly changed:
temp = (x = xx - 1.0) + 5.5;
x = xx - 1.0
temp = (xx - 1.0) + 5.5

temp = (x + 0.5) * log(temp) - temp;

The thing that may be getting you depending ont he original code is any implicit casting going on between the variables temp, x and xx. Make sure nothing is getting cast to anything less than a float and the log will make the value useless if you are losing precision somewhere in the conversion.

If you can test it with a manual calulation break down each calculation step to one pair and display the results to check everything matches what you expect it to be.