Invalid operands to binary ^ (have 'double' and 'double')

Question

Hi all,
I've been trying to make some calculus like
double a, b, c;
b = 0.3;
c =0.35;
a = b^c;
but I get this error message: *"Invalid operands to binary ^ (have 'double' and 'double')"*. Does anybody know how to solve this?
Thanks in advance!

Answer 1

Yes I think Ray hit the nail on the head. It looks as if you wanted to perform and exponentiation operation, not a bitwise operation. So, just to expand on Ray's answer a bit, the carrot symbol (^) that you used in your statement is, in C, the bitwise XOR operator, and has nothing to do with exponentiation. There are numerous bitwise operators in C (bitwise AND (&), bitwise OR (|), bitwise XOR (^)), and they all deal with manipulating bits of data. If you were, in fact, trying to raising b to the power of c and assign that value back to a, then Ray's post was the perfect answer as to how to do that.
Many programmers that are new to C, especially ones coming from a language such as Visual Basic, where the carrot symbol is used for exponentiation operations, naturally try to use the same symbol for the same purpose in C, and are surprised to find that it doesn't do what they expected (understandably). As mentioned, this is because, in C, there is no exponentiation operator, and the carrot symbol does something completely different and unrelated to exponentiation. However, C does provide a predefined function in its standard library for exponentiation, and it is called the pow() function, which takes two double-typed arguments (the first is the number being risen and the second is the power that it is being raised to), and returns the result as a double. To use this function, all you have to do is write an include directive at the top of the file that you will be using the function in that tells the preprocessor to include the file math.h. See RayNewb's post for a solid example of how all this stuff would look in your source code, and, as he mentioned, open your Terminal and type in +man math+ or, for this particular function, +man pow+ to find out more about how this function works (you can page through the information with the spacebar or scroll down with the down arrow).
Hope this was of some help for you, and best of luck with everything!