The difference between the post-increment and pre-increment matters if you try to combine them into a larger expression.
Post-increment (count++) will increase it's value after doing all of the other operations Pre-increment (++count) will increase it's value before doing all of the other operations
Look at these two lines of code: a) result = count++ * 5; b) result = ++count * 5;
If starting with count = 8: (a) will multiply 8 * 5, and store the 40 into result, then it will increase count to 9. (b) will first increase count to 9, then multiply 9 * 5 and store 45 into result