As you step through the do loop, when you get to the expression j-- < 7, remember (or save) the current value of j, decrement j, then use the saved value of j to test j < 7. When you get to the expression i++ < 7, remember (or save) the current value of i, increment i, then use the saved value of i to test i < 7. Here is the first time through the loop: evaluate 9 < 4 decrement j to 8 before evaluating 9 < 7 increment i to 1 increment i to 2 before evaluating 1 < 7