List and describe eight of the statements used in Java programs to alter or control the logical flow of the program.

Answer 1

Provide pseudo-code that illustrates the general syntax of a while statement.

Answer 2

True or false? During the execution of a while statement, the program will continue to execute the statement or compound statement for as long as the conditional expression evaluates to true, or until a break or continue statement is encountered. If false, explain why.

Answer 3

True or false? A while loop is an entry condition loop. If false, explain why.

Answer 4

What is the significance of an entry condition loop?

Answer 5

Provide pseudo-code illustrating the general syntax of the if-else statement.

Answer 6

Provide pseudo-code illustrating the general syntax of the switch-case statement.

Answer 7

Describe the behavior of a switch-case statement. Provide a pseudo-code fragment that illustrates your description of the behavior. Do not include a description of labeled break statements.

Answer 8

What are the three actions normally involved in the operation of a loop (in addition to executing the code in the body of the loop) ?

Answer 9

True or false? A for loop header consists of three clauses separated by colons. If false, explain why.

Answer 10

Provide pseudo-code illustrating the general syntax of a for loop

Answer 11

True or false? In a for loop, the first and third clauses within the parentheses can contain one or more expressions, separated by the comma operator. If False, explain why.

Answer 12

What is the guarantee made by the comma operator ?

Answer 13

True or false? The expressions within the first clause in the parentheses in a for loop are executed only once during each iteration of the loop. If false, explain why.

Answer 14

While any legal expression(s) may be contained in the first clause within the parentheses of a for loop, the first clause has a specific purpose. What is that purpose?

Answer 15

True or false? Variables can be declared and initialized within the first clause in the parentheses of a for loop. If false, explain why.

Answer 16

True or false? The second clause in the parentheses of a for loop consists of a single expression which must eventually evaluate to true to cause the loop to terminate. If false, explain why.

Answer 17

True or false? A for loop is an exit condition loop. If false, explain why.

Answer 18

True or false? Because a for loop is an entry condition loop, the third clause inside the parentheses is executed at the beginning of each iteration. If false, explain why.

Answer 19

True or false? A return statement is used to terminate a method and (optionally) return a value to the calling method. If False, explain why.

Answer 20

True or false? Exception handling modifies the flow of control of a Java program. If false, explain why.

Answer 21

What is the meaning of the following two images?

This image was inserted here simply to insert some space between the questions and the answers to keep them from being visible on the screen at the same time.

The image is also an example of the kinds of things that we do in my course titled ITSE 2321, Object-Oriented Programming.

This image was also inserted for the purpose of inserting space between the questions and the answers.

True.

Back to Question 21

True.

Back to Question 20

False. Although the third clause appears physically at the top of the loop, it isn't executed until the statements in the body of the loop have completed execution. This is an important point since this clause is typically used to update the control variable, and perhaps other variables as well. If variables are updated in the third clause and used in the body of the loop, it is important to understand that they do not get updated until the execution of the body is completed.

Back to Question 19

False. The value of the second clause is tested when the statement first begins execution, and at the beginning of each iteration thereafter. Therefore, the for loop is an entry condition loop.

Back to Question 18

False. The second clause consists of a single expression which must eventually evaluate to false (not true) to cause the loop to terminate.

Back to Question 17

True.

Back to Question 16

Typically the first clause is used for initialization. The intended purpose of the first clause is initialization.

Back to Question 15

False. The expressions in the first clause are executed only once, at the beginning of the loop, regardless of the number of iterations.

Back to Question 14

The comma operator guarantees that its left operand will be executed before its right operand.

Back to Question 13

True.

Back to Question 12

The general syntax of a for loop follows:

for (first clause; second clause; third clause)
  single or compound statement

Back to Question 11

False: A for loop header consists of three clauses separated by semicolons, not colons.

Back to Question 10

The operation of a loop normally involves the following three actions in addition to executing the code in the body of the loop:

Back to Question 9

The pseudo-code fragment follows:

switch(expression){
  case constant:
    sequence of optional statements
    break; //optional
  case constant:
    sequence of optional statements
    break; //optional
.
.
.
  default //optional
    sequence of optional statements
}

An expression is tested against a series of unique integer constants. If a match is found, the sequence of optional statements associated with the matching constant is executed. Execution of statements continues until an optional break is encountered. When break is encountered, execution of the switch statement is terminated and control is passed to the next statement following the switch statement.

If no match is found and the optional default keyword along with a sequence of optional statements has been provided, those statements will be executed.

Back to Question 8

The general syntax of the switch-case statement follows:

switch(expression){
  case constant:
    sequence of optional statements
    break; //optional
  case constant:
    sequence of optional statements
    break; //optional
.
.
.
  default //optional
    sequence of optional statements
}

Back to Question 7

The general syntax of the if-else statement is:

if(conditional expression)
  statement or compound statement;
else //optional
  statement or compound statement; //optional

Back to Question 6

The significance of an entry condition loop is that the conditional expression is tested before the statements in the loop are executed. If it tests false initially, the statements in the loop will not be executed.

Back to Question 5

True.

Back to Question 4

True.

Back to Question 3

The general syntax of a while statement follows :

while (conditional expression)
   statement or compound statement;

Back to Question 2

The following table lists the statements supported by Java for controlling the logical flow of the program.

Statement            Typeif-else              selection
switch-case          selection
for                  loop
for-each             loop
while                loop
do-while             loop
try-catch-finally    exception handling
throw                exception handling
break                miscellaneous
continue             miscellaneous
label:               miscellaneous
return               miscellaneous
goto                 reserved by Java but not supported

Back to Question 1