The document discusses various aspects of control structures in programming languages including: 1. Control structures define control statements and the blocks of code they control. 2. Selection structures determine code execution based on expressions and can be nested, requiring disambiguation rules. 3. Loop structures iterate code execution and consider the type, scope and evaluation of loop variables and parameters. 4. Common loop types include counting loops, pretest loops where expressions are evaluated before each iteration, and posttest loops where expressions are evaluated after code execution. Language designs balance flexibility with reliability in loop structures.

1. Chapter 8 review questions:
1.What is the definition of control structure?
A control structure is a control statement and the collection of
statements whose execution it controls.
2.What is the definition of block?
It is a continuous set of statements that does specific task.
3.What are the design issues for selection structure?
What is the form and type of the expression that controls the
selection?
How are the then and else clauses specified?
How should the meaning of nested selectors be specified?
4.What are the common solutions to the nesting problem for tow-way
selectors?
1- A static semantic rule is used to provide disambiguation.
2- Use alternative means of forming compound statement.
5. What are the design issues for multiple selection statements?
What is the type of the expression that controls the selection?
How are the selectable segments specified?
Is execution flow through the structure restricted to include just a
single selectable segment?
How should unrepresented selector expression values be handled,
if at all?
6.What is unusual about C's multiple selection statement? What design
trade-off was made in this design ?
It allows control to flow through more than one selectable code segment
on a single execution. And the designers of C's multiple selection traded
a decrease in reliabilityfor an increase in flexibility.

2. 7.Explaine how C#'s switch statement is safer than that in Java.
A static semantic rule disallows the implicit execution of more than one
segment.
8. what are the design issues for counter-controlled loop statement?
What are the type and scope of the loop variable?
What value does the loop variable have at loop termination?
Should it be legal for the loop variable or loop parameters to be
changed in the loop, and if so, does the change affect loop
control?
Should the loop parameters be evaluated only once, or once for
every iteration?
9. What is a pretest loop statement? What is a posttest loop statement?
Pretest: is a logically controlled loop where the Boolean expression is
evaluated before entering the body of the loop.
Posttest: is a logically controlled loop where the Boolean expression is
evaluated after entering the body of the one time.
10. What are the difference between the for statement of C++ and that
of Java?
Loop control expression is restricted to Boolean.
11. What are the design issues for logically controlled loop statement?
Should the control be pretest or posttest?
Should the logically controlled loop be a special form of a counting
loop or separate statement?
12. What is the main reason user-located loop control statement where
invented?
To make it more convenient for programmers to choose a location for
loop control other than the top or bottom of the loop.

3. 13. What advantage does C#'s break statement have over C's break
statement?
It includes labels that specify which loop is to be continued.
14. What are the differences between the statement of C++ and that of
Java?
Exist of labels.
15. What is a user-defined iteration control?
It is the iteration based on data structures.