If statement format flow

if The sentence format is

        if( Relationship expression ){

                Statement of body ;               

        }

Execute the process ：

        1. First calculate the value of the relational expression

        2. If the value of the relationship expression is true Execute the body of the statement

        3. If the value of the relationship expression is false Do not execute the statement body

        4. Continue to execute the following statements

public class IfDemo{
    public class void main (String []args){
        // Defining variables 
        int a =2;
        int b = 4;
        if(a==b){
            System.out.println("a be equal to b");
        }
       System.out.println(" It's not equal to ");
    }
}

If so a=b Then it will be output "a be equal to b", If ah ！=b Then it will output " It's not equal to ".

This format is written to feel good , But one drawback is that only one condition can be set , If there is a second condition, it can no longer be realized . So there will be if sentence .

if.......else

Format ：

        if( Relationship expression ){

        Statement of body 1

        }else{

         sentence 2

        }

Execute the process ：

1.   First calculate the value of the relational expression
2. If the value of the relationship expression meets the first condition , Then execute the statement body 1
3. If the value of the relational expression does not meet the first condition and meets the second condition , Then execute the statement body 2
4. Continue to execute the following statements

public class IfDemo{
    public static void main(String []args){
        // Define two variables 
        int a = 3;
        int b = 6;
        if(a>b){
        System.out.println("a Greater than b")
        }else{
        System.out.println("a The value is less than b")
        }
    }
}

This code has two different conditions , If you meet the first one, go the first one , Then the second one won't be executed again .

In line with the second, it will go directly into the second instead of going into the first and coming out again .

use if Sentence to solve

Segmentation of scores

 public class IfDemo{
	public static void main (String []args){
        int score =(int)(100*Math.random());
		System.out.println(" The score is "+score+" Belong to ");
		if (score>=90){
			System.out.println(" Great ");
		}else if (score>=80){
			System.out.println(" just so so ");
		}else if(score>=60){
			System.out.println(" Just passed. ");
		}else{
			System.out.println(" I didn't do well in the exam ");
		}
    }
}