bluej - I've been tasked to put this formula to sum 48. Logically it does sum up but I don't know why it rationally sums up 47

Question

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Since the variables are a=11, b=3, c=19; I wrote a formula that would sum to 48 like (c++ + a--) + (c++ - b--) when looked logically, (20 + 10) + (20 - 2) which should sum up to 48, but the output is 47.

question from:https://stackoverflow.com/questions/65895358/ive-been-tasked-to-put-this-formula-to-sum-48-logically-it-does-sum-up-but-i-d

Answer 1

Pay attention to the difference x++ and ++x and x=x+1, simply you can regard x++ as the following 2 steps:

1. return x for computing
2. x=x+1

and the ++x means:

1. x=x+1
2. return x for computing

So, the code you write actually compute (19 + 11) + (20 - 3) = 47, and finally a=10, b=2, c=21.