C++ Math log()
The function is used to find the natural logarithm (base-e logarithm) of a given number.
Mathematically:
Suppose ‘x’ is a given number:
Syntax
Parameter
x: It is the value whose natural logarithm is to be calculated.
Return value
Following are the return values of a given number:
| Parameter(x) | Return value |
|---|---|
| x>1 | Positive |
| x=1 | 0 |
| 1>x>0 | Negative |
| x=0 | -infinty |
| x<0 | Not a Number(nan) |
Example 1
Let’s see a simple example when the value of x is 1.
Output:
Value of x is : 1 Log value of x is : 0
In this example, the value of x is 1. Therefore, the function log() returns the positive value i.e 0.
Example 2
Let’s see another simple example
Output:
Value of x is : 3 Log value of x is : 1.09861
In this example, the value of x is 3. Therefore, the function log() returns the positive value i.e 1.09861
Example 3
Let’s see a simple example when the value of x is -0.5.
Output:
Value of x is : -0.5 Log value of x is : nan
In this example, value of x is -0.5. Therefore, the function log() returns the Not a Number(nan).
Example 4
Let’s see a simple example when the value of x is 0.
Output:
clValue of x is : 0 Log value of x is : -inf
In this example, value of x is -1. Therefore, the function log() returns nan(Not a Number).
Example 5
Let’s see a simple example when the value of x is 0.8.
Output:
Value of x is : 0.8 Log value of x is : -0.223144
In this example, value of x is 0.8. Therefore, the function log() returns the negative value i.e -0.22