Java Decision Making Statement
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Decision Making Statement in Java
Decision making
statement statements is also called selection statement. That is depending
on the condition block need to be executed or not which is decided by
condition. If the condition is "true" statement block will be
executed, if condition is "false" then statement block will not be
executed. In java there are three types of decision making statement.
- if
- if-else
- nested if statement
- switch
1). if-then Statement
if-then is most basic statement of Decision making statement. It
tells to program to execute a certain part of code only if particular condition
is true.
Syntax
if(condition)
{
Statement(s)
}
Example if statement
class Hello
{
int a=10;
public static void main(String[] args)
{
if(a<15)
{
System.out.println("Hello good
morning!");
}
}
}
Output
Hello good morning
2). if-else statement
In general it can be
used to execute one block of statement among two blocks, in java languageif and else are the keyword in java.
Syntax
if(condition)
{
Statement(s)
}
else
{
Statement(s)
}
........
In the above syntax whenever condition is true all the if block
statement are executed, remaining statement of the program by neglecting. If
the condition is false else block statement executed and neglecting if block
statements.
Example if else
import java.util.Scanner;
class Oddeven
{
public static void main(String[] args)
{
int no;
Scanner s=new Scanner(System.in);
System.out.println("Enter any number
:");
no=s.nextInt();
if(no%2==0)
{
System.out.println("Even
number");
}
else
{
System.out.println("Odd number");
}
}
}
Output
Enter any number :
10
Even number
- 3). Nested if statement
It
is always legal to nest if-else statements which means you can use one if or
else if statement inside another if or else if statement.
Syntax
public static void main(String args[]) {
if( x == 30 ) {
It
is always legal to nest if-else statements which means you can use one if or
else if statement inside another if or else if statement.
Syntax
The
syntax for a nested if...else is as follows −
if(Boolean_expression 1) {
//
Executes when the Boolean expression 1 is true
if(Boolean_expression 2) {
//
Executes when the Boolean expression 2 is tr ue
}
}
You
can nest else if...else in the similar way as we have nested if statement.
Example
public class Test {
public static void main(String args[]) {
int x = 30;
int y = 10;
if( x == 30 ) {
if( y == 10 ) {
System.out.print("X = 30 and Y = 10");
}
}
}
}
This
will produce the following result
Output
X = 30 and Y = 10
4). Switch Statement
The switch statement in java
language is used to execute the code from multiple conditions or case. It is
same like if else-if ladder statement.
A switch statement work with byte, short, char and int primitive
data type, it also works with enumerated types and string.
Syntax
switch(expression/variable)
{
case
value:
//statements
// any number of case statements
break;
//optional
default: //optional
//statements
}
Rules for apply switch
statement
With switch statement use only byte, short, int, char data type
(float data type is not allowed). You can use any number of case statements
within a switch. Value for a case must be same as the variable in switch.
Limitations
of switch statement
Logical operators cannot be used with switch statement. For
instance
Example
case k>=20: // not allowed
Example of switch case
import java.util.*;
class switchCase
{
public static void main(String arg[])
{
int ch;
System.out.println("Enter any number
(1 to 7) :");
Scanner s=new Scanner(System.in);
ch=s.nextInt();
switch(ch)
{
case 1:
System.out.println("Today is
Monday");
break;
case 2:
System.out.println("Today is
Tuesday");
break;
case 3:
System.out.println("Today is
Wednesday");
break;
case 4:
System.out.println("Today is
Thursday");
break;
case 5:
System.out.println("Today is
Friday");
break;
case 6:
System.out.println("Today is
Saturday");
break;
case 7:
System.out.println("Today is
Sunday");
default:
System.out.println("Only enter value
1 to 7");
}
}
}
Output
Enter any number (1 to
7) :
5
Today is Friday
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