指示流程控制语句
ThirdJava.java
public class ThirdJava {
    public static void main(String args[]) {
        boolea b = true;
        
        if (b) {
            // do something
        }
        if (b) {
            System.out.println(b);
        }
        else {
            System.out.println("if else 语句");
        }
        //注释
        //for 语句
        for (int i = 0; i < 9; i ++) {
            System.out.println(i + " ");
        }
        /*注释*/
        /*do while语句*/
        do {
           //一些语句
        }while(条件)
        while(条件) {
            //一些语句
        }
        switch (一个整形) {
            case 一个整形:
                //一些语句
                break;
            //其他的case
        }
    }
}
前面三个为快速入门