In C does the logical operator end if one side of a || is true? [duplicate]

Answer 1

In C, the logical || operator is tested from left-to-right, guaranteed. For the whole statement to be true, either condition can be true. So || keeps going from left to right until one condition is true, and then stops (or it gets to the end). So no, if abc(1) returns true then abc(2) will not be called.

Contrast with &&, which keeps going from left to right until one condition is false (or it gets to the end).

Answer 2

No. It's guaranteed (by The Standard), that if abc(1) returns true, abc(2) will NOT be called.

If abc(1) returns false, that it's guaranteed, that abc(2) WILL be called.

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It's similar with &&: if you have abc(1) && abc(2), abc(2) will be called ONLY IF abc(1) return true and will NOT be called, if abc(1) return false.

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The idea behind this is:

true OR whatever -> true
false OR whatever -> whatever

false AND whatever -> false
true AND whatever -> whatever

This comes from the boolean algebra