Java之面向对象3.3.3--一切皆对象

package com.javase06.obj3;

public class Count {

// 类方法
public static int counter(String str, String word) {

int count = 0;
int index = -1;
do {
index = str.indexOf(word); // 返回word子字符串在str中首次出现的下标
if (index >= 0) { // 找到子字符串
count++;
str = str.substring(index + word.length()); // 剩余的字符串
}
} while (index >= 0);

return count;

}

}

package com.javase06.obj3;

public class PrimeNumber {

private int num;

public PrimeNumber(int num) {
this.num = num;
}

// 判断是否为质数的方法
public boolean isPrime() {
boolean flag = true; // true表示是质数

if (num == 1) {
return false;
} else if (num == 2) {
return true;
} else {
for (int i = 2; i < num; i++) {
if (num % i == 0) {
flag = false;
break;
}
}
return flag;
}
}

/*
* public static boolean isPrime(int num){
*
* boolean flag= true; //true表示是质数
*
* if(num==1){ return false; }else if(num==2){ return true; }else{ for(int
* i=2;i<num;i++){ if(num%i==0){ flag=false; break; } } return flag; }
*
*
*
* }
*/

}

package com.javase06.obj3;

//学生信息类
public class Student {

// 国籍
public static String country;

// 学号、姓名、性别、年龄，java成绩
private int no;
private String name;
private String sex;
private int age;
private double java;

// 构造方法
public Student(int no, String name, String sex, int age, double java) {
this.no = no;
this.name = name;
this.sex = sex;
this.age = age;
this.java = java;
}

// setter
public void setNo(int no) {
this.no = no;
}

3ff0
public void setName(String name) {
this.name = name;
}

// getter
public int getNo() {
return no;
}

public String getName() {
return name;
}

public String getSex() {
return sex;
}

public int getAge() {
return age;
}

public double getJava() {
return java;
}

// 计算两个学生的平均java成绩
public static double getAvg(Student stu1, Student stu2) {
return (stu1.getJava() + stu2.getJava()) / 2;
}

}

package com.javase06.obj3;

//测试学生信息类
public class Test4 {
public static void main(String args[]) {

System.out.println("国籍：" + Student.country);
// 设置静态属性值
Student.country = "中国";
Student stu1 = new Student(1001, "张三", "女", 20, 90.0);
System.out.println("学生学号:" + stu1.getNo() + ",姓名：" + stu1.getName() + ",性别：" + stu1.getSex() + ",年龄："
+ stu1.getAge() + ",java成绩：" + stu1.getJava() + ",国籍：" + stu1.country);

Student stu2 = new Student(1002, "李四", "男", 25, 95.0);
System.out.println("学生学号:" + stu2.getNo() + ",姓名：" + stu2.getName() + ",性别：" + stu2.getSex() + ",年龄："
+ stu2.getAge() + ",java成绩：" + stu2.getJava() + ",国籍：" + stu2.country);

// 修改国籍
stu1.country = "日本";
System.out.println("学生学号:" + stu1.getNo() + ",姓名：" + stu1.getName() + ",性别：" + stu1.getSex() + ",年龄："
+ stu1.getAge() + ",java成绩：" + stu1.getJava() + ",国籍：" + stu1.country);

System.out.println("学生学号:" + stu2.getNo() + ",姓名：" + stu2.getName() + ",性别：" + stu2.getSex() + ",年龄："
+ stu2.getAge() + ",java成绩：" + stu2.getJava() + ",国籍：" + stu2.country);

// 调用静态方法
double avg = Student.getAvg(stu1, stu2);
System.out.println("平均java成绩：" + avg);

}
}

package com.javase06.obj3;

import java.util.Scanner;

public class Test6 {
public static void main(String args[]) {

//
Scanner scan = new Scanner(System.in);

System.out.println("请输入一个整数：");

int x = scan.nextInt();

PrimeNumber pn = new PrimeNumber(x);
boolean flag = pn.isPrime();

// boolean flag = PrimeNumber.isPrime(x);
if (flag) {
System.out.println(x + "是质数");
} else {
System.out.println(x + "不是质数");
}

}
}

package com.javase06.obj3;

public class Test7{
public static void main(String args[]){

String str = "hellojsj&8hellohajkhello**90hello";
String word = "hello";

int count = Count.counter(str,word);

System.out.println(str+"中"+word+"出现的次数："+count);

}
}