Control Statements

In java there are two types of Statements. They are:

• Sequential Statements (statements which are executed one by one.)
• Control Statements (Statements which are executed repeatedly and randomly)

When we come to control statements, these are again divided into 3. they are:

• Conditional or Decision Making statements(if-then, if-then-else, switch)
• Looping Statements(for, while, do-while)
• Branching Statements(break, continue, return)

if..else statement:

This statement performs the task based on the condition. The statements present inside the curly braces {} represents a task. The following is the syntax of this statement.

fig: if-else statement

switch statement:

This statement consists of a set of cases which we have to choose according to our requirement. This statement is mainly used in menu driven programs. The following figure shows the syntax:

fig: Switch statement

break statement:

This statement is used to break the flow of execution. This is used in 3 places, they are:

• used in switch statement to come out of it.
• used in loops to come out of it.
• used in nested blocks to go to the end of the block.

continue statement:

This statement is used to skip the iteration of loops. The following program shows the use of continue statement. 

fig: continue statement

return statement:

Return statement is used to exit form the method. This statement has two forms, one which returns a value and one which doesn't.        

while loop:

The statements present in this loop executes continuously as long as the condition specified in the loop is true. The following is the syntax for while loop.

fig: while statement

do...while loop:

The difference between while and do-while is that, In while loop, first the condition is checked and then the block of code is executed, where as in do-while first the block of code is executed and then the condition is evaluated. This means in do-while the block of statements are executed atleast once. The following is the syntax of do-while.

fig: doWhile statement

for loop :

This loop iterates over a range of values, the following is the syntax of for loop.

fig: for loop

for-each loop:

This loop is mainly used in collections. This loop repeatedly executes the statements for each element of a collection. The no.of iterations of this loop is equal to no.of elements in the collection. The following is the syntax. 
                                                       

fig: for each loop