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

How do I raise a number to a power?

2^1

2^2

2^3

etc...

From stackoverflow

• pow() in the cmath library. More info here.

  Nils Pipenbrinck : hell, yes.. it's really that simple..

  Joey Robert : Easy reputation.

• pow

• Use the pow(x,y) function: See Here

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

• It's pow or powf in <math.h>

  There is no special infix operator like in Visual Basic or Python

  newacct : powf() is a C99 function that is not in C++.

• pow(2.0,1.0)
  pow(2.0,2.0)
  pow(2.0,3.0)
  

  Your original question title is misleading. To just square, use 2*2.

• 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

• While pow( base, exp ) is a great suggestion, be aware that it typically works in floating-point.

  This may or may not be what you want: on some systems a simple loop multiplying on an accumulator will be faster for integer types.

  And for square specifically, you might as well just multiply the numbers together yourself, floating-point or integer; it's not really a decrease in readability (IMHO) and you avoid the performance overhead of a function call.

  leander : And yeah, this may fall into the "premature optimization" category, but I always find it good to be aware of things like this -- especially if you have to program in limited-resource environments.

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

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

  pow(2.0, N)
  

• I think, if you use the way which you know, it will be better.. here it is..

  #include <math.h>
  
  
  struct float_t
  {
  
      float value;
  
      float_t(float v)
      {
       value = v;
      }
      operator float()
      {
       return value;
      }
      float operator ^(float c)
      {
       return powf(value, c);
      }
  };
  
  int _tmain(int argc, _TCHAR* argv[])
  {
  
      float_t num(4);
      printf("%f", num ^ 3);
  }