The log() function defined in the math.h header file. It helps to return the natural logarithm (base-e logarithm) of the given argument value.
double log(double x); #where x should be in double
Also, two functions logf() and logl() were used with type float and long double respectively.
float logf(float x);
long double logl(long double x);
The log() function takes a single parameter in double.
Parameter | Description | Required / Optional |
---|---|---|
x | whose natural logarithm needs to be found | Required |
The return value of log() function is a number in float.
Input | Return Value |
---|---|
x > 0 | Finds the log of the argument |
x < 0 | Shows run-time error |
#include <stdio.h>
#include <math.h>
int main()
{
double N = 5.6, output;
output = log(N);
printf("The value of log(%.1f) is %.2f", N, output);
return 0;
}
Output:
The value of log(5.6) is 1.72
#include <stdio.h>
#include <math.h>
int main () {
double k, out;
k = 2.7;
out = log(k);
printf("The value of log(%lf) is %lf", k, out);
return(0);
}
Output:
The value of log(2.700000) = 0.993252