Raising to powers in C++ vs. Python

Question

Coming from Python, I've noticed things in C++ tend to be a little more complicated. A good example would be raising numbers to a power. In Python's math library, all that is needed is:

a = a**b

However, in C++ I've found explanations in online documentation such as.....

//float
pow( float base, float exp );
//double      
pow( double base, double exp );
//long double 
pow( long double base, long double exp );
//float
pow( float base, int iexp );
//double      
pow( double base, int iexp );
//long double 
pow( long double base, int iexp );
//promoted    
pow( Arithmetic1 base, Arithmetic2 exp );

Obviously the creators of C++ must have had great reasons for making it this way, but as a new programmer, those reasons elude me. Does this give greater flexibility over the answer? What benefits have I been given here in C++ in terms of powers?

Answer 1

The multiple declarations you found are a result of C++ having static types vs. Python's dynamic types. In Python when you call a function on a value it can determine at runtime if you are calling it on an integer, float, or some more complex object and take the appropriate actions. In C++ you can't call the same function with different types so you must declare a different version of the function for all the types you wish to support. However unlike in C, you can have functions with the same name that differ only in their parameter signature, (as Untitled123 points out, this is called function overloading). This actually makes your life easier since you can just call pow(a,b) without having to worry about which special function to call for the types you want (e.g. pow_float_int(a,b) or pow_float_float(a,b)), the compiler will call the correct version for you based upon the types of the arguments.

Answer 2

Numbers in python have no limit. Some consequences that arise out of this is that programs tend to be slower since python is not statically typed, and has more overhead since it does not know if a number is within a certain range. In short, the main reason for using overloading functions in that way is for speed purposes, and it's easier to reason about what's happening under the hood. Python provides a lot of conveniences, but sometimes become very difficult to reason about.

Secondly, most languages have a math.pow function (Java also for example), and while it's a bit verbose, I think it's still very easy to understand. Note that when you call pow() in C++, the compiler will figure out which of the pow(some data type, some data type) should be called and there is no need to worry over the multiple definitions.