a mock exam question

[suneeta prattipati]

Hi everyone,
I need an explanation for the foll ques from Mind Qclass MyPoint
{ void myMethod()
{ int x, y;
x = 5; y = 3;
System.out.print( " ( " + x + ", " + y + " ) " );
switchCoords( x, y );
System.out.print( " ( " + x + ", " + y + " ) " );
}
void switchCoords( int x, int y )
{ int temp;
temp = x;
x = y;
y = temp;
System.out.print( " ( " + x + ", " + y + " ) " );
}
}
What is printed to standard output if myMethod() is executed?
a) (5, 3) (5, 3) (5, 3)
b) (5, 3) (3, 5) (3, 5)
c) (5, 3) (3, 5) (5, 3)

[Jonathan Jeban]

The Answer is (c).
Reason : Whatever changes u make inside a method will not be reflected back . Remember u are sending only a copy of the
parameters to the method.
Hope this helps...
Jeban

[anrup kris]

(5,3)(3,5)(5,3) would be printed out to standard output.
When you enter amethod() and execute :
System.out.print( " ( " + x + ", " + y + " ) " );
(5,3) is written out.
Then a copy of the instance variables is passed to the method
switchCoords(x,y).Here x and y are arguments to switchCoords() method and are local to the method.The coordinates are swapped,and (3,5) gets printed in the System.out.print() call
from within switchCoords() method.
The instance variables x,y are unaltered by the switchCoords() call.So the next print stmt writes out (5,3)
Hope this helps

[suneeta prattipati]

Hi Jonathan & Anrup,
Thanks. I got it now.