C++ 控制小数位

#include <iostream>
#include <iomanip>
#include <cmath>


using namespace std;


int main()
{
	double r;
	while(cin>>r) {
	    r = r>=0?r:-r;
	    cout << setiosflags(ios::fixed) << setprecision(2) << r << endl;
	}
	return 0;
}