Why does the following expression:
total += *start++;
Evaluate to:
total += (*start)++;
And not:
total += *(start++); // though this doesn't really matter either it would be the same
The ++ (postfix increment) and * (dereference have the same precedence and associate from right-to-left, so why isn't the ++ postfix evaluated first?
Or, does the postfix evaluate after a sequence point, and so:
total += *++start
Would evaluate to:
total += *(++start)
But because the postfix happens after:
total += *start++
Would evaluate to:
total += (*start)++;
In other words, Right-to-Left associativity is not important in the above expression, because even post-fix is evaluated after not during the expression evaluation?
The postfix ++ operator does have higher precedence than the dereference operator *. So the expression parses as:
total += *(start++);
What might be confusing you is that the result of the postfix ++ operator is the operand before it is incremented. The actual increment happens as an unsequenced side effect of the expression.
So this expression takes the original value of start, dereferences it, and adds that value to total. By the time the expression is fully evaluated, start is incremented.
Note that this differs from:
total += (*start)++;
Because this increments what start points to instead of start itself.