acos (<valarray>)
Operates on the elements of an input valarray, returning a valarray whose elements are equal to the arccosine of the elements of the input valarray.
template<class Type>
valarray<Type> acos(
const valarray<Type>& _Left
);
Parameters
- _Left
The input valarray whose elements are to be operated on by the member function.
Return Value
A valarray whose elements are equal to the arccosine of the elements of the input valarray.
Remarks
The units of the returned elements are in radians.
The return value is a principal value between 0 and +pi that is consistent with the cosine value input.
Example
// valarray_acos.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>
int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;
valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] = 0.25 * i - 1;
valarray<double> va2 ( 9 );
cout << "The initial valarray is:";
for (i = 0 ; i < 9 ; i++ )
cout << " " << va1 [ i ];
cout << endl;
va2 = acos ( va1 );
cout << "The arccosine of the initial valarray is:\n";
for (i = 0 ; i < 9 ; i++ )
cout << setw(10) << va2 [ i ]
<< " radians, which is "
<< setw(11) << (180/pi) * va2 [ i ]
<< " degrees" << endl;
}
The initial valarray is: -1 -0.75 -0.5 -0.25 0 0.25 0.5 0.75 1
The arccosine of the initial valarray is:
3.14159 radians, which is 180 degrees
2.41886 radians, which is 138.59 degrees
2.0944 radians, which is 120 degrees
1.82348 radians, which is 104.478 degrees
1.5708 radians, which is 90 degrees
1.31812 radians, which is 75.5225 degrees
1.0472 radians, which is 60 degrees
0.722734 radians, which is 41.4096 degrees
0 radians, which is 0 degrees
Requirements
Header: <valarray>
Namespace: std