Answer :
Explanation:
Your problem arises in the user input. When taking a user input, and using the input() function, you need to ask the user something:
Instead of:
miles_per_gallon = float(input())
You need to enter text in the form:
miles_per_gallon = float(input("Enter a value: "))
This may be the format in which you included your code but remember, indentation is important so lines 3, 9, and 12 need to be indented.
Hope this helps!

Answer:Change your logic to:
for (int i = 0; i < 4; i++) {
System.out.println("Please input a number between zero to 3");
// use input and don't advance the scanner every time
int input = sc.nextInt();
if (input == 0) {
System.out.println("You have selected " + right);
}
if (input == 1) {
System.out.println("You have selected " + left);
}
// so on and so forth
}
By using sc.nextInt() four times, you are looking for the next token of the input which isn't there. So fetch the input for each run of the for-loop and it will work as expected.
Explanation: