The log2() function is used to return the logarithm to base-2 of the argument passed to it.
double log2(double x);
float log2(float x);
long double log2(long double x);
double log2(T x); // For integral type
The log2() function takes only one parameter with a value between zero and infinity.
The log2() function returns the logarithm of a number in base-2.
When the argument passed to the function is less than zero, the function returns NaN (Not a Number).
The table below shows the return value of the log2() function for any given input:
| Parameter (x) | Return value |
|---|---|
| x < 0 | NaN (Not a Number) |
| x > 0 | Positive |
| x = 1 | Zero |
| x = 0 | negative infinity (-∞) |
#include <iostream>#include <cmath>using namespace std;int main (){// creating a variableint x = 1000, result;// using the log2() functionresult = log2(x);cout << "log2(x) = " << result << endl;x = -3.591;result = log2(x);cout << "log2(x) = " << result << endl;return 0;}
x.log2() function on the x variable and assign the output to another variable, result.result variable.We replicate the same code but with a different argument value in the rest of the code.