What is the C++ function to raise a number to a power?

Question

pow() in the cmath library. More info here. Don't forget to put #include<cmath> at the top of the file.

std::pow in the <cmath> header has these overloads:

pow(float, float);
pow(float, int);
pow(double, double); // taken over from C
pow(double, int);
pow(long double, long double);
pow(long double, int);

Now you can't just do

pow(2, N)

with N being an int, because it doesn't know which of float, double, or long double version it should take, and you would get an ambiguity error. All three would need a conversion from int to floating point, and all three are equally costly!

Therefore, be sure to have the first argument typed so it matches one of those three perfectly. I usually use double

pow(2.0, N)

Some lawyer crap from me again. I've often fallen in this pitfall myself, so I'm going to warn you about it.

In C++ the "^" operator is a bitwise OR. It does not work for raising to a power. The x << n is a left shift of the binary number which is the same as multiplying x by 2 n number of times and that can only be used when raising 2 to a power. The POW function is a math function that will work generically.

You should be able to use normal C methods in math.

#include <cmath>

pow(2,3)

if you're on a unix-like system, man cmath

Is that what you're asking?

Sujal

Use the pow(x,y) function: See Here

Just include math.h and you're all set.