log2()

The log2() function returns the base-2 logarithm of the argument.

Syntax

log2(x)

If the x parameter is negative (less than zero), then a domain error will occur. If x is equal to zero, a pole error may occur where the result has reached the point of infinity and cannot be returned.

Example

The following example uses the log2() function to find the base-2 log of 1024:

#include <iostream>
#include <cmath>
using namespace std;
int main() {
double x = 1024;
double result;
result = log2(x);
cout << "The log to the base of 2 of " << x << " is " << result << "\n";
// Output: The log to the base of 2 of 1024 is 10
}

Codebyte Example

The following example is runnable and returns the base-2 log of 8:

Code
Output
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