Wednesday, 16 August 2017

Java Dicision Making

    Decision making is one of the serious facilities which a programming language has to grant. To understand Java better we have to understand this post and practice by writing some decision making code
    There are two types of decision making statements in Java. One is very usually used which is If statement and you will find it about in every piece of code. Second is Switch statement.

If statement: 

The if statement is Java’s conditional branch statement.it return true or false.

If the Boolean expression is evaluated to true, statement(s) inside the body of if (statements inside parenthesis) are executed.


Syntax
If(Boolean expression)
{
     // Code here
}

Example :

Code
public class if_demo
{
     public static void main(String args[])
      {
         int iNum1 = 20;
         int iNum2 = 10;
         if(iNum1>iNum2)
         {
             System.out.println("iNum1 is greater than iNum2");
          }
                               
    }
}
Output:
iNum1 is greater than iNum2


if else :

    This if else work like : if condition is true than statement1 is executed or else statement2 is executed.

    If the Boolean condition is evaluated to true, statement(s) inside the body of if (statements inside parenthesis) are executed.

    If the Boolean condition is evaluated to false, statement(s) inside the body of if are skipped from execution.

Syntax
if(Boolean condition)
{
                // statement1
}
else
{
                // statement2
}


Example : 

Code
public class if_else_demo
{
   public static void main(String args[])
   {
                int iNum1 = 10;
                int iNum2 = 20;
                if(iNum1>iNum2)
                {
                    System.out.println("iNum1 is greater than iNum2");
                }
                else
                {
                    System.out.println("iNum2 is less than iNum1");
                }
    }
}
Output:
iNum2 is less than iNum1


If-else if

    The if statement executed from top to down. the moment one of the condition is true, statement associated with that if statement executed.
    If none of the condition is true than else statement will be executed, only one of the statement executed from list of else if statements.


Syntax
if(Boolean condition)
{
                // statement1
}
else if(Boolean condition)
{
                // statement2
}
else if(Boolean condition)
{
                // statement3
}
........
else
{
                // else statement
}


Example:

Code
public class if_else_if_demo
{
   public static void main(String args[])
   {
                int prsntg = 60;
                if(prsntg >= 70)
                {
                     System.out.println("First class with Distinction");
                }
                else If(prsntg >= 60)
                {
                    System.out.println("First Class");
                }
                else If(prsntg >= 50)
                {
                     System.out.println("Second Class");
                }
                else If(prsntg >= 35)
                {
                    System.out.println("Pass Class");
                }
                else
                {
                    System.out.println("Fail");
               }

   }
}
Output:
First Class


switch statement:

    Switch statement give an easy way to send off execution to dissimilar parts of your code based on the value of an expression. It is use to replace multilevel if-else-if statement. But the switch statement can only be used if the conditions are based on the same regular value. The syntax for switch statement is :

Syntax
switch(expression)
{
case value 1:
                // statement 1
                break;
case value 2:
                // statement 2
                break;
case value n:
                // statement n
                break;
default:
                //statements
                break;
}

Example : 

Code
public class switch_case_demo
{
                public static void main(String args[])
                {
                int iDay = 5;
                switch(iDay)
                {
                case 1:
                                System.out.println("Today is Monday");
                                break;
                case 3:
                                System.out.println("Today is Tuesday");
                                break;
                case 4:
                                System.out.println("Today is Wednesday");
                                break;
                case 5:
                                System.out.println("Today is Thursday");
                                break;
                case 6:
                                System.out.println("Today is Friday");
                                break;
                case 7:
                                System.out.println("Today is Saturday");
                                break;
                default:
                                System.out.println("Today is Sunday");
                                break;
                }
                }
}
Output:
Today is Thursday
  
    In this post we learned if, if else, if else if, switch case with example,


    In next post we will learn about array in java.

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