main.cpp

易学c++源码

#include "iostream.h"
#include "math.h"
double cos(int a);
void main()
{
	int i;
	cin >>i;
	cout <<cos(i) <<endl;
}
double cos(int a)
{
	int temp;
	temp=(((a/180)%2)==0?1:-1);
	return temp*sqrt(1-(sin(a/180.0*3.141592653)*sin(a*3.141592653/180)));
}