Consider the following loop, where n is some positive integer.

for (int i = 0; i < n; i + = 2) {

if ( / * condition to test * / ) {

/ * perform some action * /

}

}

In terms of n, which Java expression represents the maximum number of times that / * perform some action * / could be executed?

a. (n + 1) / 2

b. n / 2

c. (n - 1) / 2

d. n

e. n-1

Question

Computers & Technology

Ana Peterson

17 September, 14:41

Consider the following loop, where n is some positive integer.

for (int i = 0; i < n; i + = 2) {

if ( / * condition to test * / ) {

/ * perform some action * /

}

}

In terms of n, which Java expression represents the maximum number of times that / * perform some action * / could be executed?

a. (n + 1) / 2

b. n / 2

c. (n - 1) / 2

d. n

e. n-1

+2

Answers (2)

Know the Answer?

Elise · Answer 1

We first look at the loop:

i=0 to i
means

i goes from 0 to n-1 in steps of 2.

For the step of 2, we conclude immediately that the value of n must be divided by two, whether we add or subtract constants from it.

As long as n>=0, the number of times execution proceeds is (n-1) / 2 (because i
(i-1) / 2 + 1 = (i+1) / 2.

We still need to check at least two values of n ( = odd and even).

n=7, execution cases are 0,2,4,6 totaling 4. (7+1) / 2 = 4, good!

n=8, execution cases are 0,2,4,6 again totalling 4. ((8+1) / 2) = 9/2 = 4 (integer division truncates) So again it is correct.

So the answer choice is (n+1) / 2.

Natasha Moore · Answer 2

a.

Explanation:

Suppose n=7, then the loop will be executed for i=0, 2, 4 and 6, so 4 times.

(int) ((7+1) / 2) = 4.

Suppose n=6, then the loop will be executed for i=0, 2 and 4, so 3 times.

(int) ((6+1) / 2) = 3.

a. is the only formula that works.