课后练习1: package two_c1; public class Season { public void spring() { System.out.println(); System.out.println("该季节为春季"); } public void summer() { System.out.println(); System.out.println("该季节为夏季"); } public void autumn() { System.out.println(); System.out.println("该季节为秋季"); } public void winter() { System.out.println(); System.out.println("该季节为冬季"); } } package two_c1; import java.util.Scanner; public class Show { public static void main(String[] args) { System.out.print("请输入月份:"); Scanner input = new Scanner(System.in);//输入月份 int month = input.nextInt(); Season show = new Season(); switch(month) { case 1: case 2: case 3: show.spring(); break;//1~3月为春天 case 4: case 5: case 6: show.summer(); break;//4~6月为夏天 case 7: case 8: case 9: show.autumn(); break;//7~9月为秋天 case 10: case 11: case 12: show.winter(); break;//10~12月为冬天 } } } 课后练习3: package two_c3; public class Calculator { public void add(int a,int b) { System.out.println(a + "+" + b + "=" + (a+b));//加法 } public void minus(int a,int b) { System.out.println(a + "-" + b + "=" + (a-b));//减法 } public void multiple(int a,int b) { System.out.println(a + "*" + b + "=" + (a*b));//乘法 } public void divide(int a,int b) { System.out.println(a + "/" + b + "=" + ((double)a/b));//除法 } } package two_c3; import java.util.Scanner; public class Show { public static void main(String[] args) { System.out.print("请输入第一个数:"); Scanner input = new Scanner(System.in); int a = input.nextInt();//输入第一个整数a System.out.print("请输入运算符:"); char operator = input.next().charAt(0);//输入运算符 System.out.print("请输入第二个数:"); int b = input.nextInt();//输入第二个整数b Calculator show = new Calculator(); switch(operator) { case '+': show.add(a,b);//调用加法方法 break; case '-': show.minus(a,b);//调用减法方法 break; case '*': show.multiple(a,b);//调用乘法方法 break; case '/': show.divide(a,b);//调用除法方法 break; } } } 课后练习4: package two_c4; import java.util.Scanner; public class QuessMachine { String name; int money; int guessMoney; public void goods(int random) { switch(random) { case 0: name = "洗衣机"; money = 1000; break; case 1: name = "电视机"; money = 3000; break; case 2: name = "自行车";//定义三个奖品信息 money = 400; break; } } public void guess() { System.out.print("请猜测“"+name+"”的价格:"); Scanner input = new Scanner(System.in); guessMoney = input.nextInt(); for (int i = 0; i < 3; i++) { if (guessMoney == money) { System.out.println("恭喜你,获得"+name);//如果猜对,获得奖品 break; } else if(guessMoney > money) { System.out.println("再小点!");//如果猜大了,提示再小点 } else { System.out.println("再大点!");//如果猜小了,提示再大点 } System.out.print("再猜一次吧:"); guessMoney = input.nextInt(); if(i == 2 && guessMoney == money) { System.out.println("恭喜你,获得"+name);//最后一次猜对,获得奖品 break; } } if (guessMoney != money) { System.out.println("4次内没有猜对,下次努力吧!");//全部猜错,提示下次努力 } } } package two_c4; public class Show { public static void main(String[] args) { QuessMachine show = new QuessMachine(); int random = (int)(Math.random()*3);//产生0、1、2三个随机数,对应三个商品 show.goods(random); show.guess(); } } 课后练习5: package two_c5; public class Calculator { public double ope(int op,int num1,int num2) { double result = 0; switch(op) { case 1: result = num1 + num2; break; case 2: result = num1 - num2; break; case 3: result = num1 * num2; break; case 4: result = (double)num1 / num2;//根据输入的数字,进行加减乘除四种运算 break; } return result; } } package two_c5; import java.util.Scanner; public class Show { public static void main(String[] args) { System.out.print("请选择运算:1.加法 2.减法 3.乘法 4.除法:"); Scanner input = new Scanner(System.in);//手动选择运算 int op = input.nextInt(); System.out.print("请输入第一个数:"); int num1 = input.nextInt(); System.out.print("请输入第二个数:"); int num2 = input.nextInt(); Calculator show = new Calculator(); System.out.println("***运算结果为:"+show.ope(op, num1, num2));//输出结果 } } 课后练习6: package two_c6; public class InsertArray { public void insertArray(int[]arr,int index,int value) { if(index == arr.length-1) { arr[index] = value;//如果选择插入的位置为最后一位,特殊处理 }else { for (int i = arr.length-1; i > index; i--) { arr[i] = arr[i-1];//选择插入位置之后的位置元素后移 } arr[index] = value;//把输入的元素插入到指定位置 } for (int i = 0; i < arr.length; i++) { System.out.print(arr[i]); if(i < arr.length-1) { System.out.print(",");//输出插入后的数组 } } } } package two_c6; import java.util.Scanner; public class Show { public static void main(String[] args) { Scanner input = new Scanner(System.in); InsertArray show = new InsertArray(); int[] arr = new int[6]; arr[0] = 9; arr[1] = 5; arr[2] = 5; arr[3] = 2; arr[4] = 1; System.out.print("请输入需要插入的整数:");//输入插入的数 int value = input.nextInt(); System.out.print("请输入需要插入的下标:");//输入插入的下标 int index = input.nextInt(); show.insertArray(arr, index, value); } } 课后练习7:
package two_c7; public class Student { int java; int c; int sql;//定义三门科目属性 public double getAvg(Student stu) { double avg = (double)(java+c+sql)/3;//计算平均成绩 return avg; } } package two_c7; import java.util.Scanner; public class StudentBiz { public static void main(String[] args) { Student stu = new Student(); Scanner input = new Scanner(System.in); System.out.print("请输入Java成绩:"); stu.java = input.nextInt(); System.out.print("请输入C#成绩:"); stu.c = input.nextInt(); System.out.print("请输入SQL成绩:");//输入成绩 stu.sql = input.nextInt(); System.out.println("三门科目的平均分是:"+stu.getAvg(stu));//调用并显示方法 } }