Overview


Sending messages to methods that return values is done the same way as simple messages.

The only difference is that the return value may be used by the caller.

Our Previous Code
Here is our previous code. 
Rectangle rec;
rec = new Rectangle();

rec.setSmall();
Getting The Return Value
Recall from our previous work here... that the method "getWidth" returns an "int" value.

  • Send the message "getWidth" to the "rec" object
  • Assign the returned value to the var "w"

Variable names like "w" here are coder's choice -- we could use "w", "width", "ww", "fred", etc 
Rectangle rec;
rec = new Rectangle();

rec.setSmall();

int w;

2
w = 
1
rec.getWidth();
Other Uses For A Return Value
We can also use the return value anywhere the type is valid. In this case the value type is "int".


  • We use the value 10 in a summation which is fine (10 is an "int" data type)
  • But we can also use the return value from getWidth() (also an "int")
Rectangle rec;
rec = new Rectangle();

rec.setSmall();

int sum;


sum = 
1
10 + 20;

sum = 
2
rec.getWidth() + rec.getHeight();






























Introduction To Objects With Java (Chapter 403 - Using Objects)










Chapter 403 - Using Objects Sending Messages That Return Value

Contents Overview Using Variables Constructing Method "main" Sending Messages Example Challenge

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