The Comma Operator

The comma operator strings together several expressions. The left side of the comma operator is
always evaluated as void. This means that the expression on the right side becomes the value of the
total comma-separated expression. For example,
x = (y=3, y+1);
first assigns y the value 3 and then assigns x the value 4. The parentheses are necessary because the
comma operator has a lower precedence than the assignment operator.
Essentially, the comma causes a sequence of operations. When you use it on the right side of an
assignment statement, the value assigned is the value of the last expression of the comma-separated
list.
The comma operator has somewhat the same meaning as the word "and" in English, as used in the
phrase "do this and this and this."