Lecture 13: Statement-Level Control Structures

what is a control statement

Statements that provide capabilities such as selecting among alternative control flow paths or causing the repeated execution of certain collection of statements

what are selection statments

[1] Selection statements: choose between two or more execution paths in a program. [2] Two-way selection statements: select one of two execution paths [3] Multiple-selection statements: select one of many execution paths,

give an example of Two-way selection statements

if-then-else statements.

give an example of Multiple-selection statements:

Switch statements.

what are Iterative Statements

[1] Mechanism for the repeated execution of a statement or a compound statement. [2] It is implemented either by various loops (iteration) or recursion

whata re the 2 forms of Logically-Controlled Loops

Pre-test and Post-test

explain pre-test lopps

Pre-test: Loop condition is tested before execution of loop body. In most languages: while loop. Pascal: while ... do.

explain post-test loops

Post-test: loop body is executed before condition is tested. Loop body is executed at least one time. Normally: do ... while. In Pascal: repeat ... until.

what is Unconditional Branching

statements that change control follow without any condition

give some examples of unconditional branching statmens

break, continue, and return.

what does bnreak do?

break provides unconditional exits from loops.

What does continue do?

continue skips the remainder of the current iteration, but does not exit the loop.

What does return do?

return terminates function/method calls.

what does an Unlabelled break break do

An unlabelled break statement terminates switch, for, while, or do-while statement. It terminates the innermost of such statements when they are nested.

What does a labled break do?

A labeled break terminates an labelled statement and control flow is transferred to the statement immediately following the labelled (terminated) control statement.