Unexpected type resulting from the ternary operator

by

You’re seeing an effect similar to the one in this question.

Slightly different rules govern the way Java handles types with the ternary operator than with an if statement.

Specifically, the standard says:

The type of a conditional expression is determined as follows:

…

Otherwise, if the second and third operands have types that are
convertible (§5.1.8) to numeric types, then there are several cases:

…

Otherwise, binary numeric promotion (§5.6.2) is applied to the
operand types, and the type of the conditional expression is the
promoted type of the second and third operands.

Flipping to that page of the standard, we see:

If either operand is of type double, the other is converted to double.

which is what’s happening here, followed by autoboxing to a Double. It appears that no such conversion happens with the if statement, explaining the difference.

More broadly — this isn’t a very good idea. I don’t think it’s good design to return one of an int or a double depending on the value — if you want to round something off, use Math.floor, and if you don’t want decimals printed, use printf.

EDIT: I don’t think it’s a good idea to do hacky things to circumvent the regular numeric conversion system. Here’s an idea that gives you a String directly, which appears to be what you want:

static String convert3(double d) {
    return ((d % 1 == 0) ? Integer.toString((int)d) : Double.toString(d));
}

More Related Contents:

  1. Write 1 line If statement using ternary operator in JAVa
  2. What is the Java ?: operator called and what does it do?
  3. What is a Question Mark “?” and Colon “:” Operator Used for? [duplicate]
  4. Ternary Operator – JAVA [duplicate]
  5. Ternary Operators Java
  6. Why does the ternary operator unexpectedly cast integers?
  7. Java Ternary without Assignment
  8. Why doesn’t this method work? Java ternary operator
  9. “Wrong” return type when using if vs. ternary opertator in Java
  10. Why ternary operation gives nullpointer while its ifelse counterpart doesn’t? [duplicate]
  11. ternary operator not working
  12. For Loop different type on how to code [closed]
  13. Virtual Memory Usage from Java under Linux, too much memory used
  14. How to terminate Scanner when input is complete?
  15. Eclipse error: “The import XXX cannot be resolved”
  16. What’s the difference between fx:id and id: in JavaFX?
  17. Dynamic code execution
  18. ArrayList initial capacity and IndexOutOfBoundsException [duplicate]
  19. Validate JAXBElement in JPA/JAX-RS Web Service
  20. How to match “any character” in regular expression?
  21. Is it worth to use slf4j with log4j2
  22. javac error: Class names are only accepted if annotation processing is explicitly requested
  23. Is there any sizeof-like method in Java?
  24. Remove end of line characters from Java string
  25. How can we redirect a Java program console output to multiple files?
  26. Java: Non-static nested classes and instance.super()
  27. Will the jit optimize new objects
  28. JPA using multiple database schemas
  29. Running javafx sample on JDK 11 with OpenJFX 11 JMODS on Module Path
  30. JPA Updating Bidirectional Association

Leave a Comment