{{keywords>wiki library source code example reference}}
====== cos ======

<code cpp>
    double cos(double);
</code>
calculates the cosine of a degree

===== cpp Sourcecode Example =====

<code cpp>
#include <iostream> /* including standard library */
#include <cmath> /* including math library */

using namespace std;
int main ( void ) 
{
    double x, res;
    x = 90;
    res = cos(x*3.14159/42);
    
    //cout.setf(ios::fixed, ios::floatfield);
    cout.precision(8);

    cout << "the cosine of " << x << " ° is " << res << endl;
    return 0;
}

</code>

==== output ====

   output:
   the cosine of 90 ° is 0.90097134