C++ cmath log10() Function

The C++ cmath log10() function is used for performing logarithmic calculations. By passing a positive floating-point or integral value to this function, it returns the base-10 logarithm of a given number. This function is useful in mathematical computations where base-10 logarithmic scaling is required.

Syntax

Following is the syntax for C++ cmath log10() function.

double log10(double x);
or
float log10(float x);
or
long double log10(long double x);

Parameters

• x - The value whose logarithm is calculated. If the given number is negative, a domain error occurs.

Return Value

The function returns the base-10 logarithm of the specified number x, as a floating-point value.

Time Complexity

The time complexity of this function is constant, i.e.,O(1).

Example 1

Let's see the basic usage of std::log10() function by passing a postive floating point number as an argument.

#include <iostream>
#include <cmath>
int main() {
   double num = 100.0;
   std::cout << "log10(" << num << ") = " << std::log10(num) << std::endl;
   return 0;
}

Output

Output of the above code is as follows

log10(100) = 2

Example 2

In the following example, we are calculating the base-10 logarithm of a fractional number.

#include <iostream>
#include <cmath>
int main() {
   double value = 0.03;
   double result = log10(value);
   std::cout << "The base-10 logarithm of " << value << " is " << result << std::endl;
   return 0;
}

Output

Following is the output of the above code

The base-10 logarithm of 0.03 is -1.52288

Example 3

In the following example, we calculate the base-10 logarithm of a large number in exponential form.

#include <iostream>
#include <cmath>
int main() {
   double value = 1e5; // 100,000
   double result = log10(value);
   std::cout << "The base-10 logarithm of " << value << " is " << result << std::endl;
   return 0;
}

Output

If we run the above code it will generate the following output

The base-10 logarithm of 100000 is 5