Questions tagged [pow]

The pow(...) function is a mathematical function commonly featured in most programming language libraries. The pow function represents exponentiation. It takes in two numerical arguments a, b, and returns another numerical value, a to the power of b.

In mathematical notation, we write a^b, or if space isn't enough, a^b using the caret. Note that the caret operator may indicate bitwise XOR notation instead. Some languages use the double-asterisk operator ** as an equivalent to pow(a,b).

Usages:

• C/C++: double pow(double x, double y)
  • Including a header <math.h> is required for C/C++.
  • powf is for floats, powl is for long doubles.
• Erlang: math:pow(X, Y)
• Java: Math.pow(double x, double y), returns double
• JavaScript: Math.pow(number, number) (note all JS numbers are floating-point number type)
• C#: double Pow(double x, double y) (capital Pow)
• Python: math.pow(x, y) (Equivalent to x**y, but it converts both arguments to floating-point values unlike **).

Equivalent notations

• Lua, Mathematica: x ^ y (^ could mean bitwise OR in other languages)
• Python, Ruby: x ** y
  • Python also have a three-argument pow(x, y, z), which computes x**y modulo z.

Special Cases:

• Pow(0,0) means zero to the power of zero. Technically, it is undefined, but some implementations return 1, such as Java. Others may return NaN or even incur undefined behavior.
• Pow(x,1) sometimes returns x regardless of what value x is
• Pow(x,0) and Pow(x,±Infinity) can result in ±0 or ±Infinity based on mathematical result and the signs of the arguments.
• Pow(1,±Infinity) can result in NaN.

Related tags:

• exponentiation: What pow means
• math, math.h, standard-library: pow(...) is often a standard library function.
• xor, bitwise-xor: The caret (^) symbol often means pow aka exponentiation, but it could also mean bitwise XOR.

References:

• Wikipedia: https://en.wikipedia.org/wiki/Exponentiation#In_programming_languages (More examples)
• C/C++: http://www.cplusplus.com/reference/cmath/pow/
• C#: https://msdn.microsoft.com/en-us/library/system.math.pow(v=vs.110).aspx (Includes F# and VB usages)
• Erlang: http://erlang.org/doc/man/math.html
• Java: https://docs.oracle.com/javase/10/docs/api/java/lang/Math.html (See the pow section)
• JavaScript: https://www.w3schools.com/jsref/jsref_pow.asp
• Lua: https://www.lua.org/pil/3.1.html
• Mathematica: http://reference.wolfram.com/language/tutorial/TypingPowers.html
• Python2: https://docs.python.org/2/library/functions.html, https://docs.python.org/2/library/math.html?highlight=pow#math.pow
• Python3: https://docs.python.org/3/library/functions.html, https://docs.python.org/3/library/math.html?highlight=pow#math.pow
• Ruby: https://www.techotopia.com/index.php/Ruby_Operators