1.使用循环把26个字母按字典顺序存入数组,在不使用另外数组的情况下将其逆序存放,在根据处理后的字符数组创建一个字符串并输出 public static void main(String[] args) { char a[]=new char[26],c; //中间变量c int i; for(i=0;i<a.length-1;i++){ a[i]=(char)('a'+i); } for(i=0;i<13;i++){ c=a[i]; a[i]=a[25-i]; a[25-i]=c; } St…

引用:Java Programming Language Enhancements Java Programming Language Enhancements Enhancements in Java SE 7 Binary Literals - In Java SE 7, the integral types (byte, short, int, and long) can also be expressed using the binary number system. To specif…

import java.util.HashSet; public class JPTQuestion3 { public static void main(String[] args) { HashSet shortSet = new HashSet(); for (short i = 0; i < 100; i++) { shortSet.add(i); shortSet.remove(i - 1); } System.out.println(shortSet.size()); } } 输出:…

public class JPTQuestion2 { public static void main(String[] args) { String s3 = "JournalDev"; int start = 1; char end = 5; System.out.println(start + end); System.out.println(s3.substring(start, end)); } } 注意:这里的end是char类型,可是,输出结果和int型的end没区别.…

import javax.swing.JOptionPanepublic class welcome {public static void main(string[] arg){JOptionPane.showMessageDialog(null,“welcome to java programming!”);} } public class welcome {public static void main(string[] arg){System.out.println("welcome t…

Java Algorithm Problems 程序员的一天 从开始这个Github已经有将近两年时间, 很高兴这个repo可以帮到有需要的人. 我一直认为, 知识本身是无价的, 因此每逢闲暇, 我就会来维护这个repo, 给刷题的朋友们一些我的想法和见解. 下面来简单介绍一下这个repo: README.md: 所有所做过的题目 ReviewPage.md: 所有题目的总结和归纳(不断完善中) KnowledgeHash2.md: 对所做过的知识点的一些笔记 SystemDesign.md:…

https://docs.oracle.com/javase/7/docs/technotes/tools/windows/javac.html\ javac - Java programming language compiler Synopsis Description Options Command Line Argument Files Annotation Processing Searching for Types Programmatic Interface Examples Se…

This appendix contains suggestions to help guide you in performing low-level program design and in writing code.Naturally, these are guidelines and not rules. The idea is to use them as inspirations and to remember that there are occasional situation…

Thing C Java type of language function oriented object oriented basic programming unit function class = ADT portability of source code possible with discipline yes portability of compiled code no, recompile for each architecture yes, bytecode is "wri…

Java局部变量 局部变量声明在方法.构造方法或者语句块中: 局部变量在方法.构造方法.或者语句块被执行的时候创建,当它们执行完成后,变量将会被销毁: 访问修饰符不能用于局部变量: 局部变量只在声明它的方法.构造方法或者语句块中可见: 局部变量是在栈上分配的. 局部变量没有默认值,所以局部变量量被声明后,必须经过初始化,才可以使用. 实例变量 实例变量声明在一个类中,但在方法.构造方法和语句块之外: 当一个对象被实例化之后,每个实例变量的值就跟着确定: 实例变量在对象创建的时候创建,在对象被销毁…