$17\mathrm{.}22$ PRACTICE: Loops $($for$)*$: Output evens

$(1)$ Given positive integer n$,$ write a for loop in c $++$that outputs the even numbers from n down to $0.$ If n is odd, start with the next lower even number. Hint: Use an if statement and the $\%$ operator to detect if n is odd, decrementing n if so$.$

Enter an integer:

$7$

Sequence: $6420$

$(2)$ If n is negative, output $0.$ Hint: Use an if statement to check if n is negative. If so$,$ just set n $=0.$

Enter an integer:

$-1$

Sequence: $0$