Java If Keyword

Definition:

• The if statement specifies a section of Java code that will run if an if statement's condition is false.
• The following conditional statements can be used in Java:
  • To provide a block of program to run or execute only if a certain condition is true, then we need to use the if block to execute the program.
  • If the given or provided condition is false, then we will describe it in the else block of code that should be printed.
  • To define various code blocks to be performed, use the switch command.
  • In if-else statement, the Java keyword or reserved word else is used in executing the opposite statement to the if keyword.
• When an if statement is false, the otherwise statement is always carried out. It is a branching statement component that is optional.
•  Optional else part statements are carried out when the if statement returns false.

Syntax

Below is the declaration or Syntax of an else keyword in java programming language.

if(condition)
{
<state> //the block or portion of if statements
}
else
{
<state> //the portion or part where the else statements are involved or executed.
}

Control flow of the program starts with the if section and performs those statements if the Boolean expression is false.

Simple Example:

if(test_expression) {
//true condition is excuted in this block of statements
System.out.println("True condition: Raju is well characterised person");
}
else {// false conditional statement is executed in this portion
System.out.println("False condition:Raju is not a characterised person");
}

Let us consider the example programs to understand better about else keyword.

Examples for If Keyword in Java

Example 1:

class If{
public static void main (String args []) {
double age=21;
if(age>21) {
//It is executed if condition is true
System.out.println("you are eligible for marriage");
}
else {//executed if the given condition is false statement
System.out.println("you are not eligible for marriage ");
}
}
}

Output of the code is executed; it produced the following result:

You are not eligible for marriage

Example 2:

//A Java Program to demonstrate the use of if-else statement.  
//It is a program of odd and even number
public class If_lseEx {  
public static void main (String [] s) {  
    //variable declaration
    int integer=13;
    ///Verify whether the number is divisible by two.
    if(integer%2==0) {  
        System.out.println("Given integer is even");
    } else {  
        System.out.println("Given integer is odd");
    }  
}  
}  

Output of the given program is:

Given integer is odd

Example 3:

Example program of leap year

If a year can be divided by 4 and 400, it is a leap year. not by 100, though.

public class LeapYearEx3 {    
public static void main (String [] s) {    
double year=2020.    
    if (((year % 4 ==0) && (year % 100! =0)) || (year % 400==0)) {  
        System.out.println("The year is a leap year");
    }  
    else {  
        System.out.println("The year is not a leap year");
    }  
}    
}    

Output of the program is given by:

The year is a leap year

Example 4:

/Java programme to show how the If-else-if ladder is used.
/
It is a programme that assigns grades for failure, a D, a C, a B, an A, and an A+.
public class If_Else_IfEx4 {  
public static void main (String [] s) {  
    int score=83;


    if(score<50) {  
        System.out.println("unsuccess");
    }  
    else if(score>=50 &&score<60) {  
        System.out.println("D points");
    }  
    else if(score>=60 &&score<70) {  
        System.out.println("C points");
    }  
    else if(score>=70 &&score<80) {  
        System.out.println("B points");
    }  
    else if(score>=80 &&score<90) {  
        System.out.println("A points");
    } else if(score>=90 &&score<100) {  
        System.out.println("A+ points");
    } else {  
        System.out.println("Invalid statement!");
    }  
}  
}  

Output of the program is:

C points

Example 5:

Program to check whether a given number is POSITIVE, NEGATIVE or ZERO:

public class P_N_Ex5 {    
public static void main (String [] s) {    
    int Integer=-182;
    if (Integer>0) {  
    System.out.println("The number is positive");
    } else if (Integer<0) {  
    System.out.println("The number is negative");
    } else {  
    System.out.println("The number is zero");
   }  
}    
}    

Output of the program is

The number is negative.

Example 6:

/Java Program to Show Nested If Statements in Action.
public class NestedIfEx6 {    
public static void main (String [] s) {    
doubleyears=20;
doubleheight=120;
    //applying condition on years and height  
    if(years>=18) {    
        if(height>50) {  
            System.out.println("can donate the blood");
        }    
    }    
}}  

Output of the program is:

Can donate the blood