Briefly explain what is bad though syntactically correct, about the code please

Question

double i;
cout << "Enter input: ";
cin >> i;
cout << "result 1 = " << pow(i, pow(cbrt(i), 3.0)) << endl;
cout << "result 2 = " << i * i + 1 << endl;
cout << "result 3 = " << i + 1 << endl;

Answer 1

Here is the code:
https://code.sololearn.com/c7A18A19A9A3
Now can you please briefly explain what do you want to know?

Answer 2

This code will only run when you issue `using namespace std;` somewhere in the beginning of code. As I have read from what some seniors here wrote, it was a bad practice once we start writing a large scope project where name conflict is a possibility.

You forgot to #include <cmath> for std::cbrt().

(Personal opinion) I prefer to wrap expressions inside parentheses as much as possible (read: when I remember to), like so ...

std::cout << "result 1 = " << ( ... ) << std::endl;