20165303实验一 Java开发环境的熟悉

• 实验一简单的java程序编译及运行，文件夹的创建

   1.添加文件夹： 命令mkdir+文件夹名称
  

　　2.编译，运行Java程序 ：javac 主类名.java

　　　　　　　　　　　　　java 主类名

　　3.带包（package）编译：javac -d . 目标文件夹/主类名.java

　　　　　　　　　　　运行：java 包名.类

代码
public class shiyan2{
public static void main(String args[]){
System.out.println("shiyan");
}
}

• 实验二IDEA的使用及调试
  打开IDEA并创建一个project，然后再创建一个class
  输入代码，
  public class exp1 {
  public static void main(String[] args) {
  int i=1;
  int j=2;
  for(i=1;i<=100;i++){
  if(j<50)
  j=j+1;
  else
  j=j-2;
  }
  System.out.println(i);
  System.out.println(j);
  System.out.println(i);
  }
  }

并且运行结果如下

设置断点，并单步向下运行

单步执行循环操作，其中i，j的值在不断的改变

循环内执行特定变量调试

特定变量调试结果如下

调试一次执行

• 学生成绩管理系统
  代码如下
  import java.util.*;
  public class Main {
  public static void main(String[] args) {
  Student head = new Student();
  boolean flag = true;
  int i = 0;
  int ch;
  while (true) {
  System.out.println("Please input your choice:");
  Scanner in = new Scanner(System.in);
  System.out.println("1.Add a new student");
  System.out.println("2.Delete an existing student");
  System.out.println("3.Revise an existing student");
  System.out.println("4.Sort");
  System.out.println("5.Refer");
  System.out.println("0.Exit");
  ch = in.nextInt();
  switch (ch) {
  case 1:{
  flag = Add(head,flag);
  Print(head);
  break;
  }
  case 2:{
  Delete(head);
  Print(head);
  break;
  }
  case 3:{
  Revise(head);
  Print(head);
  break;
  }
  case 4:{
  head = Sort(head);
  Print(head);
  break;
  }
  case 5:{
  Refer(head);
  break;
  }
  case 0:{
  System.exit(0);
  break;
  }
  }
  }

  }
  static boolean Add(Student head,boolean flag){
  Student p = head;
  boolean f = flag;
  Scanner in = new Scanner(System.in);
  if (f) {
  f = false;
  }
  else {
  while (p.nextstu != null) p = p.nextstu;
  p.nextstu = new Student();
  p = p.nextstu;
  }
  System.out.println("Please input your name:");
  p.setName(in.next());
  System.out.println("Please input your ID number:");
  p.setNum(in.nextInt());
  System.out.println("Please input your score:");
  p.setScore(in.nextInt());
  return f;
  }
  static void Delete(Student head){
  Student p = head;
  Scanner in = new Scanner(System.in);
  System.out.println("Please input the ID of the student(Delete)😊;
  int id = in.nextInt();
  while (true) {
  if (p == null) {
  System.out.println("Not found!");
  return;
  }
  if (p.nextstu.getNum()!=id) p = p.nextstu;
  else break;
  }
  p.nextstu = p.nextstu.nextstu;
  return;
  }
  static void Revise(Student head){
  Student p = head;
  Scanner in = new Scanner(System.in);
  System.out.println("Please input the ID of the student(Revise)😊;
  int id = in.nextInt();
  while (true) {
  if (pnull) {
  System.out.println("Not found!");
  return;
  }
  if (p.getNum()!=id) p = p.nextstu;
  else break;
  }
  System.out.println("Please input your name(Revise)😊;
  p.setName(in.next());
  System.out.println("Please input your ID number(Revise)😊;
  p.setNum(in.nextInt());
  System.out.println("Please input your score(Revise)😊;
  p.setScore(in.nextInt());
  return;
  }
  static void Refer(Student head) {
  Student p = head;
  Scanner in = new Scanner(System.in);
  System.out.println("Please input the ID of the student(Revise)😊;
  int id = in.nextInt();
  while (true) {
  if (pnull) {
  System.out.println("Not found!");
  return;
  }
  if (p.getNum()!=id) p = p.nextstu;
  else break;
  }
  System.out.println("Name:"+p.getName() + " Num:" + p.getNum() + " Score:" + p.getScore());
  return;
  }
  static Student Sort(Student head) {
  Student p = head;
  Student p1 = p;
  Student p2;
  Student p3 = p;
  Student d = head;
  while (p3!=null) {
  while (p3 != null) {
  if (p1.nextstu.getScore() < p3.getScore()) {
  p1 = p3;
  }
  p3 = p3.nextstu;
  }
  }
  return d;
  }
  static void Print(Student head){
  Student p = head;
  while (p!=null) {
  System.out.println("Name:"+p.getName() + " Num:" + p.getNum() + " Score:" + p.getScore());
  p = p.nextstu;
  }
  }
  }

public class Student {
public String getName() {
return name;
}

public void setName(String name) {
    this.name = name;
}

public int getNum() {
    return num;
}

public void setNum(int num) {
    this.num = num;
}

public int getScore() {
    return score;
}

public void setScore(int score) {
    this.score = score;
}

private String name;
private  int num;
private int score;

Student nextstu = null;

}

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在编写程序的时候，首先遇到的问题就是整个程序的骨架应该怎么写，回想C语言当时的C语言程序管理系统，运用主函数和分函数来写，
再有就是排序的编写比较费劲。

header 1	header 2	header3
步骤	耗时	百分比
需求分析	30分钟	11%
设计	120分钟	47%
代码实现	60分钟	23%
测试	15分钟	5%
分析总结	30分钟	11%