For prefix increment:

int a=10;
printf( "%d" , ++a);
The output will be 11. I am sure you understand it why?

For postfix increment:

int a=10;
printf( "%d" , a++);
The output will be 10. It is because, the value of a is returned first then only it is increased by 1.

Here is another example:

int a=10, b;
printf( "%d" , a++);    // 10 is displayed
++a;                   // a becomes 12 after this statement
In you example, it doesn't matter if you use prefix or postfix increment but there are cases when, prefix and postfix increment gives different result.
shabbir like this