Java for Beginners: by Knowledge flow

Author:Knowledge flow [flow, Knowledge]
Language: eng
Format: epub
Publisher: Knowledge flow
Published: 2015-03-08T22:00:00+00:00

Control Statements

There three types of statements in java.

Selection statements

Iteration statements

Jump statements

Selection statements

It is to manage the flow of programs that is to be executed based on the dynamic conditions which can be only realized during the run time.

It provides flexibility.

If statement- It provides different paths for execution of program.

Syntax

If (condition provided) statement a;

Else

Statement b;

This means if the condition is true, then statement a is executed but if false then statement b is executed.

For example

int a, b;

If (x < y) a=0;

Else

b=0;

Now there is one type of procedure using if statement i.e. nested if statement and it is very common method in programming world.

For example

If (a == 10) {

If (b < 15) i = j;

If (c > 50) p = q;

Else

i = p;

}

Else

i = q;

Now, the second if statement in the parenthesis is associated with else. Another type of procedure is of using if statement is the if-else-if ladder statement.

For example

If (condition)

Statement;

Else if (condition)

Statement;

Else if (condition)

Statement;

.

.

.

.

.

Else

Statement;

Switch statements

It is a multi branched statement.

Syntax

Switch (expression)

{

Case value 1:

Statement

Break;

Case value 2:

Statement

Break;

.

.

.

Case vale n:

Statement

Break;

Default:

Statement;

}

The functioning of the switch statement is compares the given value with all the cases and when the match found the program sequence is executed.

For example

Class sampswitch {

Public static void main (string args [])

{

Switch (i)

{

Case0:

System.out.println (“i is zero.”);

Break;

Case1:

System.out.println(“i is one.”)

Break;

Default:

System.out.println (“i is greater than 4.”)

}

Output

i is zero.

i is one.

i is greater than 4.

i is greater than 4.

Example of nested switch loop program

Switch (countfigures)

{

Case 1:

Switch (targetvalue)

{//nested switch//

Case 0:

System.out.println (“target is zero”;

Break;

Case 1:

System.out.println (“target is one”;

Break;

}

Break;

Case 2: //...

Important features of switch statement are.

Switch statement can only check for equality unlike if.

There cannot be two cases constant in the same switch with identical values.

It is more effective than using the set of nested if statement.

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