C Language: log function
(Natural Logarithm)
In the C Programming Language, the log function returns the logarithm of x to the base of e.
Syntax
The syntax for the log function in the C Language is:
double log(double x);
Parameters or Arguments
- x
- A value used in the calculation of the logarithm of x to the base of e. If x is negative, the log function will return a domain error. If x is zero, the log function will return a range error.
Returns
The log function returns the logarithm of x to the base of e.
Required Header
In the C Language, the required header for the log function is:
#include <math.h>
Applies To
In the C Language, the log function can be used in the following versions:
- ANSI/ISO 9899-1990
log Example
/* Example using log by TechOnTheNet.com */
#include <stdio.h>
#include <math.h>
int main(int argc, const char * argv[])
{
/* Define temporary variables */
double value;
double result;
/* Assign the value we will calculate the log of */
value = 1.5;
/* Calculate the log of the value */
result = log(value);
/* Display the result of the calculation */
printf("The Natural Logarithm of %f is %f\n", value, result);
return 0;
}
When compiled and run, this application will output:
The Natural Logarithm of 1.500000 is 0.405465
Similar Functions
Other C functions that are similar to the log function:
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