Chapter
3: Programming Constructs
If
if (condition)
statement1;
if (condition)
statement2;
Example 1:
File name:IfDemo.java
class IfDemo{
public static void main(String args[]){
int a=10;
if(a>0)
{
System.out.println("A is positive");
}
if(a<0)
{
System.out.println("A is Negative");
}
}
}
The output appears as given below:
If else
if (condition)
statement1;
else
statement2;
Example2:
File name: IfDemo2.java
class IfDemo2{
public static void main(String
args[]){
int a,b,c;
a=20;
b=34;
c=25;
if (a>b&&a>c){
System.out.println("A is bigger");
}
else{
if(b>c){
System.out.println("B is bigger");
}
else{
System.out.println("C is bigger");
}
}
}
}
Ø The output appears as given below:
Nested
if's
A nested if is if statement that is the target of
another if or else. Nested if's are very common in programming.
File name : NestedIf.java
class NestedIf{
public static void main(String
args[]){
int m=74;
if (m>=50){
if(m>=80){
System.out.println("A Grade");
}
else{
System.out.println("B Grade");
}
}
else{
if(m>=30){
System.out.println("C Grade");
}
else{
System.out.println("Fail");
}
}
}
}
Output
The
if-else-if Ladder
A common programming construct that is based upon
a sequence of nested if's is the if-else-if.
It looks like this:
if(condition)
statement;
else
if (condition)
statement;
else if (condition)
statement;
...
else
statement;
Ø Example 3:
File name: ElseIfLadder.java
class ElseIfLadder{
public static void main(String
args[]){
int mark=65;
if(mark>=90){
System.out.println("A Grade");
}
else if(mark >=80){
System.out.println("B Grade");
}
else if(mark >=70){
System.out.println("C Grade");
}
else if (mark >=60){
System.out.println("D
Grade");
}
else{
System.out.println("F Grade");
}
}
}
The output appears as given below:
The
Conditional operator:
An alternative to use if and else statement is to use the conditional operator, sometimes called the ternary operator.
The
conditional operator is a ternary operator because it has three terms.
Syntax:
test?true:false
Example:
File name: ConOprDemo.java
class ConOprDemo
{
public static void main (String args[])
{
int x=25;
int y=10;
int z=0;
//The
smaller value is returned
z=x>y?x:y;
System.out.println("The value
is"+z);
}
}
The output appears as given below:
Swich case:
syntax
Switch(test){
case value One:
resultOne;
break;
case
value Two:
result Two;
break;
case
value Three:
result Three;
break;
-------
default:
default result;
}
Example 1:
File name: SwitchDemo.java
import java.util.*;
class SwitchDemo
{
public static void main(String args[])
{
int val1,val2;
char opr;
Scanner sc=new Scanner(System.in);
val1 = sc.nextInt();
val2 = sc.nextInt();
opr = sc.next().charAt(0);
switch (opr)
{
case '+':
System.out.println("Sum = " + (val1+val2));
break;
case '-':
System.out.println("Difference = "+ (val1-val2));
break;
case '*':
System.out.println("Product = " + (val1*val2));
break;
case '/':
System.out.println("Quotient = " + (val1/val2));
break;
default:
System.out.println("Invaild choice");
}
}
}
Output:
Looping Statements:
Java, iteration statement are for, while, and
do-while. These statements create what we commonly call loops. As you probably
know, a loops. As you probably know, a loop repeatedly executes the same set of
instructions until a termination condition is met.
For:
The for loop, repeats a statement or block of
statements some number of times until a condition is matched. for loops are
frequently used for simple iteration in which you repea a block of statements a
certain number of times and then stop, but you can use for loops for just about
any kind of loop.
The for loop in Java looks roughly like this:
Syntax
for(initialization; condition
checking;increment/decrement){
statement;
}
Ø
Example :
FFile name: ForDemo.java
class ForDemo
{
public static void main (String args[])
{
for (int i = 1; i<=5;i++)
{
System.out.print("\t"+i);
}
}
}
Ø The output appears as given below:
While loop
Syntax:
While (condition){
bodyOfLoop;
}
Ø
Example:
File name: WhileDemo.java
class WhileDemo{
public static void main (String args[]){
int nos = 1;
int x = 1;
System.out.println("First five
odd nos:\n");
while(nos<=5)
{
System.out.print("\t"+x);
x=x+2;
nos = nos+1;
}
}
}
Ø The output appears as given below:
DO........WHILE
LOOPS
The do loop is just like a
while loop, except that do executes a given statement or block until the
condition is false. The main difference is that while loops test the condition
before looping, making it possible that the body of the loop will never execute
if the condition is false the first time it's tested. do loops run the body of the loop at least
once before testing the condition. because the condition to evaluate is given at the end. do loops
look like this:
Syntax:
do{
bodyOfLoop;
}while(condition);
Example
File name: DoDemo.java
class DoDemo
{
public static void main (String args[])
{
int x=1;
do{
System.out.println("Looping,round"+x);
x++;
}while (x<=10);
}
}
Ø The output appears as given below:
Break
Ø Example:
FFile name: BreakDemo.java
class BreakDemo
{
public static void main(String args[])
{
int i=0;
while(i<10)
{
if(i==5)
{
break;
}
else
{
System.out.println(i);
}
i++;
}
}
}
Ø The output appears as given below:
Continue
class ContinueDemo
{
public static void main(String args[])
{
int i=0;
for(i=0;i<10;i++)
{
if(i==5)
{
continue;
}
System.out.println(i);
}
}
}
Labeled Loops
File name: BreakLoopDemo.java
class BreakLoopDemo{
public static void
main(String args[]){
boolean t =true;
first: {
second: {
third: {
System.out.println("Before the
break.");
if(t)
break second;
System.out.println("This
won't execute");
}
System.out.println("This
won't execute");
}
System.out.println("This is after
second block.");
}
}
}
Ø
The output appears as given below:
0 comments:
Post a Comment