How do these 2 ways of printing floats with decimal part differs?

How do these 2 ways of printing floats with decimal part differs?

#include <iostream>
using namespace std; 
int main() {
float n; 
cin >> n; 
printf("%.2f,n);
}
#include <iostream>
using namespace std; 
int main() {
float n; 
cin >> n; 
printf("%.*f,2,n);
}