-
++iwill increment the value ofi, and then return the incremented value.
i = 1;
j = ++i; //i is 2, j is 2
T& T::operator++() // pre-increment, return *this by reference
{
return *this;
}
-
i++will increment the value ofi, but return the original value that i held before being incremented.
i = 1
j = i++; //i is 2, j is 1
T T::operator++(int) // post-increment
{
T copy(*this);
++(*this);// pre-increment here seems logical
return copy;
}
For a for loop, either works, ++i seems more common. There is a couple of comments regarding the efficiency of ++i and i++. In any non-student project compiler, there will be no performance difference.
It's different for a C++ object, since operator++() is a function and the compiler can't know to optimize away the creation of a temporary object to hold the intermediate value.
