Java编程基础:数据类型与运算符详解

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Java编程是一门广泛应用于软件开发的高级编程语言,以其面向对象的特性、平台无关性和安全性而闻名。本文档提供了一个简明的Java介绍,主要涵盖了基础概念和核心语法元素。 首先,我们讨论了控制台输入和输出。在Java中,`ConsoleInput`通过`Scanner`类与用户交互,允许接收不同类型的数据,如整数(`nextInt()`)、长整数(`nextLong()`)、浮点数(`nextDouble()`)、单精度浮点数(`nextFloat()`)和字符串(`next()`)。数据读取后,可以使用`System.out.println()`进行输出。 接下来,介绍了Java的基本数据类型。它们分为原始类型(`byte`, `short`, `int`, `long`, `float`, `double`, `char`, `boolean`),其中每个类型的位宽不同,例如`byte`是8位,`int`是32位,`double`则是64位。`char`用于存储单个字符,而`boolean`仅能表示真(`true`)或假(`false`)。 在运算符部分,文档列出了关系运算符(如 `<`, `<=`, `>`, `>=`, `==`, `!=`),这些用于比较值;逻辑运算符,如短路逻辑(`&&`、`||`)以及取反(`!`)和异或(`^`),用于条件判断;还有算术运算符,包括基本的加减乘除(`+`, `-`, `*`, `/`)和求余(`%`)操作。 对于变量操作,有赋值(`=`, `+=`, `-=`等)和自增/自减(`++`, `--`)两种形式,分别对应预前和后置操作。这有助于修改变量值并在循环或条件语句中递增或递减。 最后,文档提到`switch`语句,这是一种多分支选择结构,根据给定表达式的值执行相应的代码块。每个`case`标签后面跟随一个可能的值,`break`关键字用于终止当前分支。如果所有`case`都不匹配,则执行`default`后的代码。 附带的学习资源网站www.pearsonhighered.com/liang提供了更深入的Java教程和学习材料,适合进一步提升编程技能。 本篇摘要概述了Java编程中的关键要素,从基本的输入输出、数据类型到运算符和控制结构,为初学者提供了一个快速入门的基础框架。深入理解和掌握这些内容,是成为Java开发者的基础。

补全以下代码private String cid;// Course id, e.g., CS110. private String name;// Course name, e.g., Introduce to Java Programming. private Integer credit;// Credit of this course private GradingSchema gradingSchema; //Grading schema of this course // enum GradingSchema{FIVE_LEVEL, PASS_FAIL} private Integer capacity;// Course capacity. private Integer leftCapacity;// Course capacity left. You should update the left capacity when enrolling students. private Set<Timeslot> timeslots;// One course may have one or more timeslots. e.g., a lecture in Monday's 10:20-12:10, and a lab in Tuesday's 14:00-15:50. public Course(String cid, String name, Integer credit, GradingSchema gradingSchema, Integer capacity) // constructor public void addTimeslot(Timeslot timeslot) //Record a timeslot for this course private Integer id;// A unique student id, should be an 8-digit integer: Undergraduates' ids should start with 1; Postgraduates' ids should start with 3. e.g., 12213199. private String name;// Student’s name private Map<Course, Grade> courses;// Enrolled courses, using Map structure to store course and its grade as a pair. Grade is an enum type enum Grade{PASS,FAIL,A,B,C,D,F}with an attribute: Double gradePoint protected Student(Integer id, String name) // constructor public abstract boolean canGraduate() // Checks if this student satisfies all the graduating conditions. Hint: you are allowed to change this abstract method into non-abstract to check if the student satisfies the common graduation conditions. public void enroll(Course course) // Tries to enroll the course, do some checks before enrolling. public void recordGrade(Course course, Grade grade)// Records the grade of a course that is current learning. public double getGpa() // Calculates the GPA for this student. public UndergraduateStudent(Integer id, String name)// constructor public boolean canGraduate() //Additional graduating conditions for undergraduate students public PostgraduateStudent(Integer id, String name)// constructor public boolean canGraduate() //Additional graduating conditions for postgraduate students

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