Java Conditional and Loop Statements


Java Conditional and Loop Statements
 

Java Flow Control
    i) Java Conditional Statements
    2) Java Loop Statements
--------------------------------------------------------------
i) Java Conditional Statements
> Conditional Statements are used to insert verification points and error handling.

a) Two types of Conditional statements in Java
1) if statement

2) switch Statement
------------------------
b) Types of Conditions
1) Single Condition (Positive and Negative Conditions)

Ex:

if (a > b) {
-----
----
}
---------------
if (!(a < b)){
------
----------
}
--------------------
2) Compound Condition

Ex:

if ((a > b) && (a < C)){
--------
--------
}

if ((a > b) || (a < C)){
--------
--------
}
------------------------------
3) Nested Condition

if (a>b){
 if (a>c){
  if (a>d){
}
}
}
----------------------------------
c) Usage of Conditional Statements
1) Execute a block of statements when condition is True.
Syntax:

if (Condition){
Statements
--------
---------
------
}

Example:

public class Flow Control {
    public static void main (String []args){

    int a, b;
    a=50; b=200;
       
    if (a > b){
    System.out.println("A is a Big Number");
    }
}
}
------------------------------
2) Execute a block of statements when a compound Condition is True.
Syntax:

if ((Condition1) && or || (Condition2)) {
Statements
---------
---------
}

Example:

public class FlowControl {
    public static void main (String []args){

    int a, b, c;
    a=50; b=40; c=30;
       
    if ((a > b) && (a > c)) {
    System.out.println("A is a Big Number");
    }
}
}
----------------------------
3) Execute a block of statements when condition is True, otherwise execute another block of statements.
Syntax:

if (Condition) {
Statements
---------
---------
}
else
{
Statements
---------
---------
}

Example:

public class FlowControl {
    public static void main (String []args){
    int a, b;
    a=50; b=50;
       
    if (a > b){
    System.out.println("A is a Big Number");
    }
    else
    {
    System.out.println("B is a Big Number");   
    }
}
}
------------------------------
4) Decide among several alternates (else if structure)
Syntax:

if (Condition){
Statements
-----------
}
else if (Condition) {
Statements
-----------
}
else if (Condition) {
Statements
-----------
}
else if (Condition) {
Statements
-----------
}
else
{
Statements
-----------
}

Example:

Initialize a integer variable, and Verify the Number.

if the number is in between 1 and 100 then display number is a Small Number.

if the number is in between 101 and 1000 then display number is a Medium Number.

if the number is in between 1001 and 10000 then display number is a Big Number.

if the number is more than 10000 then display number is High Number.

Otherwise display Number is either Zero or Negative number.
------------------------------------------------------
public class FlowControl {
    public static void main (String []args){
    int a =-100;
   
    if ((a >= 1) && (a <= 100)){
        System.out.println("A is a Small Number");
    }
    else if ((a > 100) && (a <= 1000)){
    System.out.println("A is a Medium Number");
    }
   
    else if ((a > 1000) && (a <= 10000)){
        System.out.println("A is a Big Number");
        }
    else if (a > 10000) {
        System.out.println("A is High Number");
        }
    else
    {
        System.out.println("A is either Zero or Negative Number");
    }
}
}
------------------------------------------
5) Execute a block of statements when more than one condition is True.
Syntax:

if(Condition){
 if(Condition){
  if(Condition){
  Statements
  --------
  --------
}

}

}
---------------------------------
Examples:
----------------------------
i) Else part for 1st condition only

public class FlowControl {
    public static void main (String []args){
    int a =10, b=80, c=7, d=2;
   
    if (a> b){
    if (a>c){
    if (a>d){
    System.out.println("A is a Big Number");
    }
    }
    }
    else
    {
    System.out.println("A is Not a Big Number");
    }
}
}
----------------------------------
ii) Else part for 2nd condition only

if (a> b){
if (a>c){
if (a>d){
System.out.println("A is a Big Number");
}
}
else
{
System.out.println("A is Not a Big Number");
}
}
---------------------           
iii) Else part for 3rd condition only
           
if (a> b){
if (a>c){
if (a>d){
System.out.println("A is a Big Number");
}
else
{
System.out.println("A is Not a Big Number");
}
}
}
--------------------------
iv) Else parts for all conditions

public class FlowControl {
public static void main (String []args){
int a =10, b=8, c=7, d=2;
   
if (a> b){
if (a>c){
if (a>d){
System.out.println("A is a Big Number");
}
else
{
System.out.println("A is Not a Big Number");
}
}
else
{
System.out.println("A is Not a Big Number");
}
}
else
{
System.out.println("A is Not a Big Number");
}
}
}
--------------------------------------           
Get Biggest number out of Four Numbers (else if and compound conditions)
public class FlowControl {
public static void main (String []args){
int a =10, b=8, c=7, d=2;
   
if ((a>b) && (a>c) && (a>d)){
System.out.println("A is a Big Number");
}
else if (((b>a) && (b>c) && (b>d))) {
System.out.println("B is a Big Number");   
}
else if (((c>a) && (c>b) && (c>d))) {
System.out.println("C is a Big Number");   
}
else{
System.out.println("D is a Big Number");
}
}
}
-----------------------------
6) Decide among several alternates (using Switch case structure)
Syntax:

switch (expression) {
case value:
Statements
-------
-------
break;
case value:
Statements
-------
-------
break;
case value:
Statements
-------
-------
break;

default
Statements
---------
---------
----------
}
---------------------------------
Example:

public class FlowControl {
public static void main (String []args){
char grade= 'X';
       
switch (grade){
   
case 'A':
System.out.println("Excellent");
break;

case 'B':
System.out.println("Well Done");
break;

case 'C':
System.out.println("Better");
break;
           
default:
System.out.println("Invalid Grade");
}
}
}
--------------------------------------------------------------
ii) Java Loop Statements
Loop statements for repetitive execution.

a) for loop

b) while loop

c) do while loop

d) Enhanced for loop
-----------------------------------------
a) for loop
Description: It repeats a block of statements for a specified number of times.

Syntax:

for (stratValue; endValue; increment/decrement){
Statements
-------
-------
}

Example1:
//Print 1 to 10 Numbers

for(int i=1; i<=10; i++){
System.out.println(i);
}
-----------------------------
Example2:
//Print 10 to 1 Numbers

for(int i=10; i>=1; i--){
System.out.println(i);
}
----------------------------------
Example3:
//Print 1 to 10 Numbers except 7

for(int i=1; i<=10; i++){
if (i != 7){
System.out.println(i);
}
-----------------------------------------
Example4:
//Print 1 to 10 Numbers except 4th number and 7th Number

for(int i=1; i<=10; i++){
if ((i != 4) && (i != 7)){
System.out.println(i);
}
}
----------------------------------------------
b) while loop
Description: It repeats a block of statements while condition is true.

Syntax:

Initialization
while (Condition){
statements
--------
-------
increment/decrement
}

Example1:
//Print 1 to 10 Numbers

int i = 1;
while (i <= 10){
System.out.println(i);
i++;
}
----------------------------------
Example2:
//Print 10 to 11 Numbers

int i = 10;
while (i >= 1){
System.out.println(i);
i--;
}
}
-------------------------------
Example3:
//Print 1 to 10 Numbers except 7

int i = 1;
while (i <= 10){
if (i != 7){
System.out.println(i);
}
i++;
}
-----------------------------------------
c) do while loop
Description: It repeats a block of statements while condition is true.
It executes a block of statements at least once irrespective of the condition.

Syntax:

Initialization
do
{
Statements
---------
---------
increment/decrement
} while (Condition);

Example:

int i = 1;
do
{
System.out.println(i);
i++;
} while (i<=10);
-----------------------------------
int i = 20;
do
{
System.out.println(i);
i++;
} while (i<=10);
-------------------------------------------
d) Enhanced for loop
It Executes all elements in an Array.

Syntax:

Array Declaration

for (declaration: Expression/Array){
Statements
------
}

Examples:

String [] languages ={"C", "COBOL", "Java"};
       
for (String lang: languages){
System.out.println(lang);
}
----------------------------------
String [] languages = new String[3];
languages[0] ="C";
languages[1] ="COBOL";
languages[2] ="Java";
   
for (String lang: languages){
System.out.println(lang);
}
---------------------------------------
int [] mathOperations = new int[3];
int a=10, b=20;
       
mathOperations[0]= a+b;
mathOperations[1]= a-b;
mathOperations[2]= a*b;
               
for (int operation: mathOperations){
System.out.println(operation);
}
---------------------------------------------
double [] mathOperations = new double[4];
double a=10, b=20;
       
mathOperations[0]= a+b;
mathOperations[1]= a-b;
mathOperations[2]= a*b;
mathOperations[3]= a/b;
       
for (double operation: mathOperations){
System.out.println(operation);
}
--------------------------------------------------

1 comments:

Hi sir.This is abhay,
I am requesting you,
In loops concept,Under while loop .Example-2,you have to change to 1 not 11(//Print 10 to 11 numbers).could you please update the print values

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