This function is defined in <cmath> header file.
[Mathematics] log10x = log10(x) [In C++ Programming]
log10() prototype [As of C++ 11 standard]
double log10 (double x); float log10 (float x); long double log10 (long double x); double log10 (T x); // For integral type
log10() Parameters
The log10() function takes a single mandatory argument in the range [0, ∞].
If the value is less than 0, log10() returns NaN (Not a Number).
log10() Return Value
The log10() function returns the base 10 logarithm of a number.
| Parameter (x) | Return VALUE |
|---|---|
| x > 1 | Positive |
| x = 1 | 0 |
| 0 > x > 1 | Negative |
| x = 0 | -∞ (- infinity) |
| x < 0 | nan (Not a Number) |
Example 1: How log10() works?
#include <iostream>
#include <cmath>
using namespace std;
int main ()
{
double x = 13.056, result;
result = log10(x);
cout << "log10(x) = " << result << endl;
x = -3.591;
result = log10(x);
cout << "log10(x) = " << result << endl;
return 0;
}
When you run the program, the output will be:
log10(x) = 1.11581 log10(x) = nan
Example 2: log10() With Integral Type
#include <iostream>
#include <cmath>
using namespace std;
int main ()
{
int x = 2;
double result;
result = log10(x);
cout << "log10(x) = " << result << endl;
return 0;
}
When you run the program, the output will be:
log10(x) = 0.30103