1. i++ will increment i and returns the i value.
2. i+1 is rvalue that wont effect i and returns i+1 value.
3. ++i, increments i and returns i+1 value;
example:
int i = 9;
int j;
j = i++;
j = i+1;
j = ++i;
so normally in stand alone expressions like
i++;
and
++i;
have no difference.but the difference comes when you use them in assign statements(as shown in example);