Java IF-else Statement

Syntax:

if (condition) {  

   //code if condition is true  

} else {  

   //code if condition is false  

}

public class IfElseExample {  

   public static void main(String[] args) {  

      int number = 13;  

      if(number % 2 == 0){  

         System.out.println("even number");  

      }else{  

         System.out.println("odd number");  

      }  

   }  

}

--------------------------------------------

Output:

odd number

Java IF-else-if ladder Statement

Syntax:

if(condition1){  

   //code to be executed if condition1 is true  

} else if(condition2){  

   //code to be executed if condition2 is true  

} else if(condition3){  

   //code to be executed if condition3 is true  

}  

...  

else{  

   //code to be executed if all the conditions are 

   //false

}

public class IfElseIfExample {  

  public static void main(String[] args) {  

    int marks = 65;  

    if(marks < 50){  

        System.out.println("fail");  

    }  

    else if(marks >= 50 && marks < 60){  

        System.out.println("D grade");  

    }  

    else if(marks >= 60 && marks < 70){  

        System.out.println("C grade");  

    }  

    else if(marks >= 70 && marks < 80){  

        System.out.println("B grade");  

    }  

    else if(marks >= 80 && marks < 90){  

        System.out.println("A grade");  

    }else if(marks >= 90 && marks < 100){  

        System.out.println("A+ grade");  

    }else{  

        System.out.println("Invalid!");  

    }  

  }  

}

--------------------------------------------

Output:

C grade

Java Switch Statement

Syntax:

switch(expression){    

   case value1:    

      //code to be executed;    

      break;  //optional  

   case value2:    

      //code to be executed;    

      break;  //optional  

   ......    

   default:     

      //code to be executed if all cases are not matched;    

}

public class SwitchExample {  

   public static void main(String[] args) {  

      int number=20;  

      switch(number){  

         case 10: 

            System.out.println("10");

            break;  

         case 20: 

            System.out.println("20");

            break;  

         case 30: 

            System.out.println("30");

            break;  

         default:

            System.out.println("Not in 10, 20 or 30");  

      }  

   }  

}  

--------------------------------------------

Output:

20

public class SwitchExample2 {  

   public static void main(String[] args) {  

      int number=20;  

      switch(number){  

         case 10: 

            System.out.println("10");  

         case 20: 

            System.out.println("20");  

         case 30: 

            System.out.println("30");  

         default:

            System.out.println("Not in 10, 20 or 30");  

      }  

   }  

}

--------------------------------------------

Output:

20

30

Not in 10, 20 or 30

Java For Loop

Java Simple For Loop

Syntax:

for(initialization;condition;incr/decr){  

   //code to be executed  

}

public class ForExample {  

   public static void main(String[] args) {  

      for(int i=1;i<=10;i++){  

         System.out.println(i);  

      }  

   }  

}

--------------------------------------------

Output:

1

2

3

4

5

6

7

8

9

10

Infinitive For Loop

public class ForExample {  

   public static void main(String[] args) {  

      for(;;){  

         System.out.println("infinitive loop");  

      }  

   }  

}

--------------------------------------------

Output:

infinitive loop

infinitive loop

infinitive loop

infinitive loop

infinitive loop

ctrl+c

Java For-each Loop

Syntax:

for(Type var:array){  

   //code to be executed  

}

public class ForEachExample {  

   public static void main(String[] args) {  

      int arr[]={12,23,44,56,78};  

      for(int i:arr){  

         System.out.println(i);  

      }  

   }  

}

--------------------------------------------

Output:

12

23

44

56

78

Java While Loop

Syntax:

while(condition){  
   //code to be executed  
}

public class WhileExample {  

   public static void main(String[] args) {  

      int i=1;  

      while(i<=10){  

         System.out.println(i++);    

      }  

   }  

}

--------------------------------------------

Output:

1

2

3

4

5

6

7

8

9

10

Java Infinitive While Loop

public class WhileExample2 {  

   public static void main(String[] args) {  

      while(true){  

         System.out.println("infinitive while loop");  

      }  

   }  

}

--------------------------------------------

Output:

infinitive while loop

infinitive while loop

infinitive while loop

infinitive while loop

infinitive while loop

ctrl+c

Java do-while Loop

do{  

   //code to be executed  

} while (condition);

public class DoWhileExample {  

   public static void main(String[] args) {  

      int i=1;  

      do{  

         System.out.println(i++);  

      }while(i<=10);  

   }  

}

--------------------------------------------

Output:

1

2

3

4

5

6

7

8

9

10

Java Infinitive do-while Loop

public class DoWhileExample2 {  
   public static void main(String[] args) {  
      do{  
         System.out.println("infinitive do while loop");  
      }while(true);  
   }  
}  

--------------------------------------------

Output:

infinitive do while loop
infinitive do while loop
infinitive do while loop
ctrl+c