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Shadowing of reference variables

 
Ranch Hand
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Hello,

Kindly look at the following program and explain why the fourth line in output is 99 instead of 420

Output
-----------
f.myBar.barNum is 28
myBar.barNum in changeIt is 99
myBar.barNum in changeIt is now 420
f.myBar.barNum after changeIt is 99

Thanks
Vivek.
 
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Please UseCodeTags the next time you post some code.
 
Christophe Verré
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In changeIt, myBar = new Bar(); is assigning a new instance to the method parameter myBar, not to the instance variable. myBar.barNum = 99 sets the instance variable to 99, because the instance variable was passed to the method (i.e. method parameter = instance variable).
 
Christophe Verré
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You can see that the instance variable doesn't change by outputting its value :
 
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