1. No output.
2. No
output.
3. You can always convert a switch statement to an equivalent if statement, but not an if statement to a switch statement. The use of the switch statement can improve readability of the program in some cases. The compiled code for the switch statement is also more efficient than its corresponding if statement.
4.
if (number % 2 == 0)
System.out.println("The number is even");
else
System.out.println("The number is odd");
5. Switch variables must be of char, byte, short, or int data types. If a break statement is not used, the next case statement is performed.
6. y is 2.
7. switch (a)
{
case 1: x += 5; break;
case 2: x += 10; break;
case 3: x += 16; break;
case 4: x += 34;
}
8. y is -1.
9. The loop body is executed nine times. The printout is 2, 4, 6, 8 on separate lines.
10. The difference between a do loop and a while loop is the order of evaluating the continue-condition and executing the loop body. In a while loop, the continue-condition is checked and then, if true, the loop body is executed. In a do loop, the loop body is executed for the first time before the continue-condition is evaluated.
11. Same.
12. The three parts in a for loop control are as follows:
The first element initializes the control variable.
The second element is a Boolean expression that determines whether the loop will repeat.
The third element is the adjustment statement, which adjusts the control variable.
for
(int i=1,i<=100,i++)
System.out.println(i);
13. The loop keeps doing something indefinitely.
14 No.
15. Yes. The advantages of for loops are simplicity and readability. Compilers can produce more efficient code for the for loop than for the corresponding while loop.
16. while loop:
long
sum = 0;
int
i=0;
while
(i<=1000)
{
sum += i++;
}
do
loop:
long
sum = 0;
int
i = 0;
do
{
sum += i++;
}
while
(i <= 1000)
17. The keyword break is used to exit the current loop. The program in this example will terminate. The output is balance is 1.
18. The keyword continue causes the rest of the loop body to be skipped for the current iteration. This while loop will not terminate because the boolean true doesn't test anything.
19. Yes.
for
(int i=1; sum<10000; i++)
sum = sum + i;
20. class TestBreak
{
public static void main(string[]args)
{
int sum = 0;
int item = 0;
do
{
item++;
sum += item;
}
while(item<5 || sum >=6)
System.out.println("The sum is
"+sum);
}
}
class
TestContinue
{
public static void main(String[] args)
{
int sum = 0;
int item = 0;
do
{
item++;
if (!(item == 2))
sum += item;
} while (item < 5);
System.out.println("The sum is "
+ sum);
}
}
21. c.
22. a.