The log() function is defined in valarray header file. This function is used to calculate natural logarithm of the value of the elements in valarray.
Syntax:
log(varr);
Parameter: This function takes a mandatory parameter varr which represents valarray.
Returns: This function returns a valarray containing the natural logarithm of all the elements.
Below programs illustrate the above function:
Example 1:-
// C++ program to demonstrate // example of log() function. #include<bits/stdc++.h> using namespace std;
int main()
{ // Initializing valarray
valarray< double >
varr = { 1, 2, 3, 4, 5 };
// Declaring new valarray
valarray< double > varr1 ;
// use of log() function
varr1 = log (varr);
// Displaying new elements value
cout << "The new valarray with"
<< " manipulated values is : "
<< endl;
for ( double & x : varr1) {
cout << x << " " ;
}
cout << endl;
return 0;
} |
Output:
The new valarray with manipulated values is : 0 0.693147 1.09861 1.38629 1.60944
Example 2:-
// C++ program to demonstrate // example of log() function. #include<bits/stdc++.h> using namespace std;
int main()
{ // Initializing valarray
valarray< double >
varr = { -1, 6, 3, 45, 5 };
// Declaring new valarray
valarray< double > varr1 ;
// use of log() function
varr1 = log (varr);
// Displaying new elements value
cout << "The new valarray with"
<< " manipulated values is : "
<< endl;
for ( double & x : varr1) {
cout << x << " " ;
}
cout << endl;
return 0;
} |
Output:
The new valarray with manipulated values is : nan 1.79176 1.09861 3.80666 1.60944