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c++operator-precedencecomma-operator

How does the comma operator work, and what precedence does it have?

How does the comma operator work in C++?

For instance, if I do:

a = b, c;

Does a end up equaling b or c?

(Yes, I know this is easy to test - just documenting on here for someone to find the answer quickly.)

Update: This question has exposed a nuance when using the comma operator. Just to document this:

a = b, c;    // a is set to the value of b!

a = (b, c);  // a is set to the value of c!

This question was actually inspired by a typo in code. What was intended to be

a = b;
c = d;

Turned into

a = b,    //  <-  Note comma typo!
c = d;
Solution

  • It would be equal to b.

    The comma operator has a lower precedence than assignment.