If Statement

I. Java if statement

Syntax

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

Example

public class IfStatementExample {
    public static void main(String[] args) {
        int x, y;
        x = 10;
        y = 20;
        if (x < y) {
            System.out.println("x is less than y");
        }
        x = x * 2;
        if (x == y) {
            System.out.println("x now equal to y");
        }
        x = x * 2;
        if (x > y) {
            System.out.println("x now greater than y");
        }
        // this won't display anything
        if (x == y)
            System.out.println("you won't see this");
    }
}

Output:

x is less than y
x now equal to y
x now greater than y

II. Java if-else statement

Syntax

if(condition){  
     statement 1; //code if condition is true  
}else{  
     statement 2; //code if condition is false  
}  

Example

public class IfElseDemo {
    public static void main(String[] args) {

        int testscore = 76;
        char grade;

        if (testscore >= 90) {
            grade = 'A';
        } else if (testscore >= 80) {
            grade = 'B';
        } else if (testscore >= 70) {
            grade = 'C';
        } else if (testscore >= 60) {
            grade = 'D';
        } else {
            grade = 'F';
        }
        System.out.println("Grade = " + grade);
    }
}

Output:

Grade = C

III. Java if-else-if statement

Syntax

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 IfElseIfStatementExample {
    public static void main(String args[]) {
        int month = 4; // April
        String season;
        if (month == 12 || month == 1 || month == 2)
            season = "Winter";
        else if (month == 3 || month == 4 || month == 5)
            season = "Spring";
        else if (month == 6 || month == 7 || month == 8)
            season = "Summer";
        else if (month == 9 || month == 10 || month == 11)
            season = "Autumn";
        else
            season = "Bogus Month";
        System.out.println("April is in the " + season + ".");
    }
}

Output:

April is in the Spring.