场宽

#include
#include
#include
using namespace std;

int a = 5;

int main()
{
     
	cout<< left<< setw(5) << a<< "!"<<endl;
	printf("%5d!\n", a);
	double n = 2.123456789;
	cout<<setiosflags(ios::fixed)<<setprecision(2)<<n<<endl;
	return 0;
}