Post-increment and pre-increment within a 'for' loop produce same output

Question

The following for loops produce identical results even though one uses post increment and the other pre-increment.

Here is the code:

for(i=0; i<5; i++) {
    printf("%d", i);
}

for(i=0; i<5; ++i) {
    printf("%d", i);
}

I get the same output for both 'for' loops. Am I missing something?

Answer 1

After evaluating i++ or ++i, the new value of i will be the same in both cases. The difference between pre- and post-increment is in the result of evaluating the expression itself.

++i increments i and evaluates to the new value of i.

i++ evaluates to the old value of i, and increments i.

The reason this doesn't matter in a for loop is that the flow of control works roughly like this:

1. test the condition
2. if it is false, terminate
3. if it is true, execute the body
4. execute the incrementation step

Because (1) and (4) are decoupled, either pre- or post-increment can be used.