CODEWITHSUNDEEP
java
MetaCoin
MetaCoin

Reputation: 67

a simple code, what is result of return?

I am a new programmer, I don't know what is the result of this return? I comment it. Is that true that there is {} follow by if()? Thank you

  public void blow(int amount)
  {
     if (this.popped)
         return;                                          //what is this? true or false
     this.radius += amount;
     if (this.radius <= this.maxRadius)
          return;                                         // what is this?
     this.radius = 0;
     this.popped = true;
 }

Upvotes: 0

Views: 85

Answers (3)

Makoto
Makoto

Reputation: 106390

First things first: one does not return values from a method that is declared to return void.

These return statements are acting as early exits; they simply force the execution of the method to stop (more formally, "completes abruptly") and return control to its caller without any result. A side-effect will occur if it advances past the first return, as the state of radius will have been altered at that point.

More formally, this is coming from the Java Language Specification on why this is permissible:

If a method is declared void, then its body must not contain any return statement (§14.17) that has an Expression, or a compile-time error occurs.

In general, it's not a good practice to have multiple exit paths, as it can make debugging a bit of a pain, and lead to confusion while reading the code.

Upvotes: 1

dramzy
dramzy

Reputation: 1429

Your method has a return type of void, which means it can't return anything. The return; statement just allows you to skip the rest of the code inside the method and exit the method.

Upvotes: 0

Aadi Droid
Aadi Droid

Reputation: 1739

This just returns the control flow back to the place from where the function was called. It terminates the execution of blow.

Edit: Since your function has a return type of void, you cannot have a value returned, so any which way you look at this the return is just to terminate the function.

This is what it is

 public void blow(int amount)
 {
     if (this.popped)
         return;                     //This stops the function right here, no lines
                                     //in the function beyond this are executed
     this.radius += amount;

     if (this.radius <= this.maxRadius)
         return;                     // same as above

     this.radius = 0;
     this.popped = true;

}

Upvotes: 0

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