EXPRESSIONS, STATEMENTS, BLOCKS AND CONTROL FLOW STATEMENTS

Question 1

What is an expression and give examples?

Answer 1

A construct made up of variables, operators, and
method invocations, constructed according to the syntax of the language, that evaluates to a single value.
• Examples of expressions:
int cadence = 0;
anArray[0] = 100;
System.out.println(“Element 1 at index 0: “ + anArray[0]);
int result = 1 + 2; if (value1 == value2)
System.out.println(“value1 == value2”);

Question 2

What are statements?

Answer 2

Statements are roughly equivalent to sentences in
natural languages. A statement forms a complete unit
of execution.

Question 3

What are expression statements?

Answer 3

Expressions that have been made into statements by terminating the expressions with a ; 
They include:
• Assignment expressions
• Any use of ++ or --
• Method invocations
• Object creation expressions
*Also for statements

Question 4

What is a block?

Answer 4

A block is a group of zero or more statements between balanced braces and can be used anywhere a single statement is allowed.

Question 5

What are the different types of control flow statements?

Answer 5

• decision-making statements (if-then, if-then-else, switch)
• the looping statements (for, while, do-while) and
• the branching statements (break, continue, return)

Question 6

What are the two types of break statements and when are they used?

Answer 6

Labeled and Unlabeled
• The unlabeled form can be used in a switch statement. It can also be used to terminate a for,
while, or do-while loop.
• The labeled break has the given expression or
statement that it terminates alongside it.

Question 7

What is the function of the continue statement?

Answer 7

The continue statement skips the current iteration of a
for, while , or do-while loop. The unlabeled form skips to the end of the innermost loop’s body and evaluates the boolean expression that controls the loop.

Question 8

What is the function and different forms of the return statement?

Answer 8

• The return statement exits from the current method, and control flow returns to where the method was invoked.
• The return statement has two forms: one that returns a value, and one that doesn’t.
• To return a value, simply put the value (or an expression that calculates the value) after the return keyword. E.g. return ++count;
NB:
• The data type of the returned value must match the type of the method’s declared return value.
• When a method is declared void, use the form of return that doesn’t return a value: return;