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System.out.println Strange output

Supun Lakshan Dissanayake
Ranch Hand

Joined: Oct 26, 2012
Posts: 135

When i compile and run the output was ba5
I need to know why the output was ba5 ??
[ my imagination = according to the sequence of line 11 output should be ab5 ]


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fred rosenberger
lowercase baba

Joined: Oct 02, 2003
Posts: 11955

Step through the code.

On line 11, you start to build your string, which has to complete before you can do the printing from this line.

you now step into the DoSomething() method. on line 3, you say "print the string "b"". That completes, putting the 'b' on the console.

you then return the 5.

that gets concatenated to the 'a', giving you the string "a5", which is then printed to the console, behind the 'b'.

There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
Kemal Sokolovic

Joined: Jun 19, 2010
Posts: 825

This is the result of operator precedence (priority). If no parentheses are used in complex expressions, operators with higher precedence are executed before those of a lower precedence. The method call operator has the highest precedence (along with indexing, postfix increment and decrement operator) so it's executed first. Since the method is invoked first, 'b' character is sent to the output and value 5 is returned from method. After that 'a' is concatenated to '5' and sent to the output so you get the result "ba5".

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Supun Lakshan Dissanayake
Ranch Hand

Joined: Oct 26, 2012
Posts: 135

I agree. Here's the link:
subject: System.out.println Strange output
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