It's pretty straightforward
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
cout << fixed << setprecision(2) << setfill('0');
cout << setw(5) << 48.3 << endl;
cout << setw(5) << 0.3485 << endl;
cout << setw(5) << 5.2 << endl;
}
Writing code like this makes me yearn for printf
however.