Java Basics Review -2 (Boolean short-circuit problem, operator precedence and reference data type)

1 short circuit with &&, when the left is false, do not execute to the right;

Short Circuit or | |, when its left is true, does not execute to the right.

2 int a=1;

if (a++==2) {

A = 7;

}

System.out.println (a);

The output is 2, because when + + is on the right side of a, the first to determine whether a is equal to 2, and then add 1, when + + on the left of a, the first to add 1, and then determine whether equal to 2

3 referencing the scanner data type format:

First in the class outside the Guide package import Java.util.Scanner;

Then create the new object in the class with the data type Scanner sc = new Scanner (system.in);

again to invoke the functionality in the object int i = Sc.nextint ();//used to receive console input numbers

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　string s = Sc.next ();//A string used to receive console input

4 referencing the random data type format

First in the class outside the Guide package import java.util.Random;

Then create the data type new object in the class                                   Random rd = new random (), and then invoke features in the object                                                 

again to invoke the functionality in the object int i = Rd.nextint (10);//random integer used to receive "0,10"

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Double s = rd.nextdouble ();//random decimals used to receive "0.0,1.0"

Java Basics Review -2 (Boolean short-circuit problem, operator precedence, and reference data type)