Basic JAVA 6

Basic JAVA 6

Java If-else Statement

The Java if statement is used to test the condition. It returns true or false. There are various types of if statement in java.

• if statement.

• if-else statement.

• nested if statement.

• if-else-if ladder

1) if statement

The if statement tests the condition. It executes the if statement if condition is true.

Syntax:

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

Example:

public class IfExample {  
public static void main(String[] args) {  
    int age=20;  
    if(age>18){  
        System.out.print("Age is greater than 18");  
    }  
}  
}  
Output:

Age is greater than 18

2) if else statement

The if-else statement also tests the condition. It executes the if block if condition is true otherwise else block.

Syntax:

if(condition){
        //code if condition is true
}else{
        //code if condition is false
} 

Example:

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

3) if else if ladder statement

The if-else-if ladder statement executes one condition from multiple statements.

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
} 

Example:

public class IfElseIfExample {  
public static void main(String[] args) {  
    int marks=65;  
      
    if(marks<50 span="" style="color: #7f0055; font-weight: bold;">System

.out.println("fail"); } else if(marks>=50 && marks<60 span="" style="color: #7f0055; font-weight: bold;">System.out.println("D grade"); } else if(marks>=60 && marks<70 span="" style="color: #7f0055; font-weight: bold;">System.out.println("C grade"); } else if(marks>=70 && marks<80 span="" style="color: #7f0055; font-weight: bold;">System.out.println("B grade"); } else if(marks>=80 && marks<90 span="" style="color: #7f0055; font-weight: bold;">System.out.println("A grade"); }else if(marks>=90 && marks<100 span="" style="color: #7f0055; font-weight: bold;">System.out.println("A+ grade"); }else{ System.out.println("Invalid!"); } } } Output: C grade 

Java Switch Statement

The Java switch statement is executes one statement from multiple conditions. It is like if-else-if ladder 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;
} 

Example:

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

Switch statement if fall-through

The java switch statement is fall-through. It means it executes all statement after first match if break statement is not used with switch cases.

Example:

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