CS320/09 Questions on Statements - Chapter 8

Question 1 Selection Statements

a. What are the design issues associated with selection statements.

b. Draw an UML class diagram of the concepts involved in a two-way selection statement using "Condition" and "Statement" as given classes. [Note].

Question 3 Multiple Selection Statements

b. Draw an UML class diagram of the concepts involved in a multiple selection statement using "Expression" and "Statement" as given classes[Note].

Question 2 Counter controlled Loops

b. Draw an UML class diagram of the concepts involved in a counter-controlled loop statement using "Variable", "Expression", and "Statement" as given classes.[Note].

Question 4 Compound Statements

b. What is the definition of a block?

c. Use a UML class diagram with statement, compound statement and block that indicates the relationships and differences between blocks and compound statements. [Note]

Question 5 Pretest and Post-test Loops

a. Give an example of a pretest loop statement and a post-test loop statement in a language and name the language.

b. What is the general form of a pretest loop in your language?

c. Show that any post-test loop in this language above can be re-programmed using a pretest loop.

d. Draw a UML class diagram of the relationship between statements, loops, pretest loops, and post-test loops[Note].

Note. The final may ask you to give a general pre-test loop and re-program it using a post-test loop, or perhaps express a counter controlled loop as a conditional loop, or even a two way selection as a multi-way selection, or vice versa.

Show that any post-test loop in C/C++/Java can be re-programmed using a pretest loop.

The general form of a pretest loop in these languages is
```
 	while( condition ) statement
```
and the general from of a post-test loop is
```
 	do
```
```
 		statement
```
```
 	while (condition)
```
The post loop form executes it's statement at least once. Then it tests to see if any repetitions are needed.
To get the same effect as
```
 	while( C ) S
```
write
```
 	if (C) do
```
```
 		S
```
```
 	while ( C )
```
which reinserts the extra test of the condition.
Similarly to show that any post-test loop in C/C++/Java can be re-programmed using a pretest loop you write.
To get the effect of
```
 	do S while(C)
```
by using a post-test loop use
```
 	S
```
```
 	while(C) S
```
Similarly with 'if' and 'switch'.
You can also reprogram all of these structures using only if, goto, and lots of labels. Can you figure out what this is:
```
 	L: S;
```
```
 	if( C ) goto L;
```
where L is a label and C a condition.

Review how you did in class

Contents

CS320/09 Questions on Statements - Chapter 8

Question 1 Selection Statements

Question 3 Multiple Selection Statements

Question 2 Counter controlled Loops

Question 4 Compound Statements

Question 5 Pretest and Post-test Loops

Question 6 Syntax for Control Structures

Review how well you did these exercises and think about how much revision you will need for the final

Note

Project Questions

Answer 5c

Review how you did in class

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