Rounding in double java

Question

public class project3 {
 public static void main(String[] args) {
 int earnedRuns = 52;
 int inningsPitched = 182;
 double ERA = (earnedRuns * 9) / inningsPitched;
 String FirstName = "Anibal";
 String LastName = "Sanchez";
 System.out.println("Pitcher's first name: " + FirstName);
 System.out.println("Pitcher's last name: " + LastName);
 System.out.println("Number of earned runs: " + earnedRuns);
 System.out.println("Number of innings pitched: " + inningsPitched);
 System.out.println(FirstName + " " + LastName + " has an ERA of " + ERA);
 }
}

The ERA comes out as 2.0 not 2.57... ect I cannot figure out why

Answer 1

Baically you're:

1. multiplying an integer by an integer -> integer (Result: 486)
2. dividing an integer by an integer -> integer (Result: 2)
3. Assign the result to an double variable -> double (Result: 2.0D)

So you first need to cast ("convert") those integers to floats or doubles.

double ERA = ((double)earnedRuns * 9) / inningsPitched;

or simpler:

double ERA = (earnedRuns * 9.0) / inningsPitched;

It's enough to cast just one integer because in java: integer * double -> double

EDIT:

The 9.0 D or 9.0 d just tells java that explicitly that 9.0 is meant to be a double. The same also works for 9.0 f or 9.0 F. This means that 9.0 is a float.

• user3316886: thank you. it was telling me to change the integers to doubles as well but that was not the assignment.
• maxammann: np and don't forget if the answer was helpful, accept it as answer :D