C++ Math log1p()
The function computes the natural logarithm of a given number plus one.
Suppose a number is ‘x’:
Syntax
Note: The return_type can be float, double or long double.
Parameter
x: The value of which logarithm is to be calculated.
Return value
| Parameter | Return value |
|---|---|
| x>0 | Positive |
| x=0 | zero |
| 0>x> -1 | Negative |
| x= -1 | -infinity |
| x<-1 | Not a Number(nan) |
Example 1
Let’s see a simple example when the value of x is greater than zero.
Output:
Value of x is : 10 log1p(x) = 2.3979
In this example, log1p() function computes the logarithm value when x is greater than zero.
Example 2
Let’s see a simple example when the value of x is zero
Output:
Value of x is : 0 log1p(x) = 0
In this example, log1p() function computes the logarithm value when the value of x is zero.
Example 3
Let’s see a simple example when the value of x is less than zero.
Output:
Value of x is : -0.5 log1p(x) = -0.693147
In this example, log1p() function computes the logarithm value when the value of x is less than zero.
Example 4
Let’s see the simple example when the value of x is -1.
Output:
Value of x is : -1 log1p(x) = -inf
In this example, log1p() function computes the logarithm value when the value of x is -1.
Example 5
Let’s see the simple example when the value of x is less than -1.
Output:
Value of x is : -3 log1p(x) = -nan
In this example, log1p() function computes the logarithm value when the value of x is less than -1.