Declare decision structure inside of a System.out.println

Question

So I am working on an assignment where I have to have a print method in a constructor that displays a distance. I also have to have three separate get methods depending on what the input is in the demo class. My question is that I am trying to write the print method to contain a decision structure based on which get is used. public void prt() { DecimalFormat formatter = new DecimalFormat("#,##0.00");

    System.out.println(
        "The time it takes the sound to travel " + distance +
         " feet through air is " + 

            if (getSpeedInAir() > 0) {
                formatter.format(getSpeedInAir());
            }

            else if (getSpeedInWater() > 0) {
                formatter.format(getSpeedInWater());
            }

            else if (getSpeedInSteel() > 0) {
                formatter.format(getSpeedInSteel());
            }

            else "error";
    ) 
}

After trying to compile I am getting the following errors.

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\GlaDOS\Desktop\JavaStuff>j Speed

C:\Users\GlaDOS\Desktop\JavaStuff>del    *.class

C:\Users\GlaDOS\Desktop\JavaStuff>javac  Speed.java
Speed.java:43: error: illegal start of expression
                                                           " feet through air is
 " + if (getSpeedInAir() > 0)

     ^
Speed.java:43: error: ';' expected
                                                           " feet through air is
 " + if (getSpeedInAir() > 0)

       ^
Speed.java:43: error: not a statement
                                                           " feet through air is
 " + if (getSpeedInAir() > 0)

                         ^
Speed.java:43: error: ';' expected
                                                           " feet through air is
 " + if (getSpeedInAir() > 0)

                            ^
Speed.java:47: error: 'else' without 'if'

                                 else if (getSpeedInWater() > 0)

                                 ^
Speed.java:56: error: not a statement

                                   "error";)

                                   ^
Speed.java:56: error: illegal start of expression

                                   "error";)

                                           ^
7 errors

C:\Users\GlaDOS\Desktop\JavaStuff>java   Speed
Error: Could not find or load main class Speed

Answer 1

You need to use a ternary operator ?: instead of if / else

... " feet through air is " + (getSpeedInAir() > 0 ? : formatter.format(getSpeedInAir()) ...

Answer 2

errror in this line

 "error";)

check this line you might write something like this

System.out.println("error");

Answer 3

There are probably many errors in your program.

1) You dont have an if statement. That is why you have got the error that else without if.

2) You last else is wrong:

else
 "error";) 

You may proably try like this:

 if(getSpeedInAir() > 0)
 {
    System.out.println("The time it takes the sound to travel " + distance +
                           " feet through air is " +formatter.format(getSpeedInAir());
 }
 else if (getSpeedInWater() > 0)
 {
   System.out.println("The time it takes the sound to travel " + distance +
                           " feet through air is " + formatter.format(getSpeedInWater());
 }
else if (getSpeedInSteel() > 0)
{
  System.out.println("The time it takes the sound to travel " + distance +
                           " feet through air is " + formatter.format(getSpeedInSteel());
}
 else
   System.out.println("The time it takes the sound to travel " + distance +
                           " feet through air is "+ "error");

or more efficiently like this:-

String s;
if (getSpeedInAir() > 0)
{
    s= formatter.format(getSpeedInAir()).toString();
}
else if (getSpeedInWater() > 0)
{
    s= formatter.format(getSpeedInWater()).toString();
}
else if (getSpeedInSteel() > 0)
{
    s= formatter.format(getSpeedInSteel()).toString();
}
else
    s= "error";

System.out.println("The time it takes the sound to travel " + distance +
                           " feet through air is " + s);

Answer 4

You can't use an if-statement inside the System.out.println like that.

You could do something with the ternary operator, but for the sake of code readability, it's probably best to just declare a variable and concatenate like so:

String speed;
if (getSpeedInAir() > 0)
{
    speed = formatter.format(getSpeedInAir()).toString();
}
else if (getSpeedInWater() > 0)
{
    speed = formatter.format(getSpeedInWater()).toString();
}
else if (getSpeedInSteel() > 0)
{
    speed = formatter.format(getSpeedInSteel()).toString();
}
else
    speed = "error";

System.out.println("The time it takes the sound to travel " + distance +
                           " feet through air is " + speed);