명품 자바 프로그래밍 4장 실습 문제 / 2021.08.02

1.

package Chapter4;
 
public class TV {
    private String manufacturer;
    private int year;
    private int size;
    
    public TV(String manufacturer, int year, int size) {
        this.manufacturer = manufacturer;
        this.year = year;
        this.size = size;
    }
    
    public void show() {
        System.out.println(manufacturer+"에서 만든 "+year+"년형 "+size+"인치 TV");
    }
    public static void main(String[] args) {
        TV myTV = new TV("LG", 2017, 32);
        myTV.show();
    }
}

 

2.

package Chapter4;
import java.util.Scanner;
 
public class Grade {
    private int math;
    private int science;
    private int english;
    
    public Grade(int math, int science, int english) {
        this.math = math;
        this.science = science;
        this.english = english;
    }
    
    public int average() {
        int sum = this.math + this.science + this.english;
        return sum / 3;
    }
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.print("수학, 과학, 영어 순으로 3개의 점수 입력>>");
        int math = scanner.nextInt();
        int science = scanner.nextInt();
        int english = scanner.nextInt();
        Grade me = new Grade(math, science, english);
        System.out.println("평균은 "+me.average());
        
        scanner.close();
    }
}
 

3.

package Chapter4;
 
public class Song {
    String title;
    String artist;
    int year;
    String country;
    
    public Song() {
        this("Dancing Queen", "ABBA", 1978, "스웨덴");
    }
    
    public Song(String title, String artist, int year, String country) {
        this.title = title;
        this.artist = artist;
        this.year = year;
        this.country = country;
    }
    
    public void show() {
        System.out.println(year+"년 "+country+"국적의 "+artist+"가 부른 "+title);
    }
    
    public static void main(String[] args) {
        Song song = new Song();
        Song newSong = new Song("Dancing Queen", "ABBA", 1978, "스웨덴");
        song.show();
        newSong.show();
    }
}

4.

package Chapter4;
 
public class Rectangle {
    int x;
    int y;
    int width;
    int height;
    
    public Rectangle(int x, int y, int width, int height) {
        this.x = x;
        this.y = y;
        this.width = width;
        this.height = height;
    }
    
    public int square() {
        return width * height;
    }
    
    public void show() {
        System.out.println("("+x+","+y+") 에서 크기가 "+width+"X"+height+"인 사각형");
    }
    
    public boolean contains(Rectangle r) {
        if(r.x > x && r.y > y) {
            if((x + width)>(r.x + r.width) && (y + height) > (r.y + r.width))
                return true;
        }
        return false;
    }
    
    public static void main(String[] args) {
        Rectangle r = new Rectangle(2, 2, 8, 7);
        Rectangle s = new Rectangle(5, 5, 6, 6);
        Rectangle t = new Rectangle(1, 1, 10, 10);
        
        r.show();
        System.out.println("s의 면적은 "+s.square());
        if(t.contains(r)) System.out.println("t는 r을 포함합니다.");
        if(t.contains(s)) System.out.println("t는 s를 포함합니다.");
    }
}
 

5.

package Chapter4;
import java.util.Scanner;
 
class Circle {
    private double x, y;
    private int radius;
    public Circle(double x, double y, int radius) {
        this.x = x;
        this.y = y;
        this.radius = radius;
    }
    public void show() {
        System.out.println("("+x+","+y+") "+radius);
    }
}
public class CircleManager{
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Circle c [] = new Circle [3];
        for(int i = 0; i <c.length; i++) {
            System.out.print("x, y, radius >>");
            double x = scanner.nextDouble();
            double y = scanner.nextDouble();
            int radius = scanner.nextInt();
            c[i] = new Circle(x, y, radius);
        }
        for(int i=0; i<c.length; i++) c[i].show();
        scanner.close();
    }
}
 
 

6.

package Chapter4;
import java.util.Scanner;
 
class Circle {
    private double x, y;
    private int radius;
    public Circle(double x, double y, int radius) {
        this.x = x;
        this.y = y;
        this.radius = radius;
    }
    public void show() {
        System.out.println("("+x+","+y+") "+radius);
    }
    public double area() {
        return this.radius * this.radius * 3.14;
    }
}
public class CircleManager{
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Circle c [] = new Circle [3];
        for(int i = 0; i <c.length; i++) {
            System.out.print("x, y, radius >>");
            double x = scanner.nextDouble();
            double y = scanner.nextDouble();
            int radius = scanner.nextInt();
            c[i] = new Circle(x, y, radius);
        }
        double area = c[0].area();
        for(int i=0; i<c.length; i++) {
            if(c[i].area() > area)
                area = c[i].area();
        }
        for(int i = 0; i<c.length; i++) {
            if(area == c[i].area()) {
                System.out.print("가장 면적이 큰 원은 ");
                c[i].show();
            }
        }
        scanner.close();
    }
}
 
 

7.

package Chapter4;
import java.util.Scanner;
 
class Day{
    private String work;
    public void set(String work) { this.work = work; }
    public String get() { return work; }
    public void show() {
        if(work == null) System.out.println("없습니다.");
        else System.out.println(work +"입니다.");
    }
}
public class MonthSchedule {
    Scanner sc = new Scanner(System.in);
    private Day [] days;
    boolean option = true;
    
    public MonthSchedule(int n) {
        days = new Day[n];
        for(int i = 0; i<days.length; i++) {
            days[i] = new Day();
        }
    }
    
    public void input() {
        System.out.print("날짜(1-30)?");
        int day = sc.nextInt();
        System.out.print("할일(빈칸없이입력)? ");
        String work = sc.next();
        days[day-1].set(work);
    }
    
    public void view() {
        System.out.print("날짜(1-30)?");
        int day = sc.nextInt();
        System.out.print(day+"의 할 일은 ");
        days[day-1].show();
    }
    
    public void finish() {
        System.out.println("프로그램을 종료합니다.");
        option = false;
    }
    
    public void run() {
        System.out.println("이번달 스케쥴 관리 프로그램.");
        while(option) {
            System.out.print("할일(입력:1, 보기:2, 끝내기:3) >>");
            int number = sc.nextInt();
            switch(number) {
                case 1:
                    input();
                    break;
                case 2:
                    view();
                    break;
                case 3:
                    finish();
                    break;
            }
        }
    }
    public static void main(String[] args) {
        MonthSchedule april = new MonthSchedule(30);
        april.run();
    }
}

8.

package Chapter4;
import java.util.Scanner;
 
class Phone{
    String name;
    String tel;
    public Phone(String name, String tel) {
        this.name = name;
        this.tel = tel;
    }
}
public class PhoneBook {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("인원수>> ");
        int person = sc.nextInt();
        Phone [] phones = new Phone[person];
        for(int i = 0; i<phones.length; i++) {
            System.out.print("이름과 전화번호(이름과 번호는 빈 칸없이 입력)>> ");
            String name = sc.next();
            String tel = sc.next();
            phones[i] = new Phone(name, tel);
        }
        System.out.println("저장되었습니다...");
        
        while(true) {
            int i = 0;
            System.out.print("검색할 이름>> ");
            String search = sc.next();
            
            for(i =0; i<phones.length; i++) {
                if(search.equals(phones[i].name)) {
                    System.out.println(search+"의 번호는 "+phones[i].tel+"입니다.");
                    break;
                }
            }
            if(search.equals("그만")) break;
            if(i == person) {
                System.out.println(search+" 이 없습니다.");
            }
        }        
        sc.close();
    }
}
 

9.

package Chapter4;
 
class ArrayUtil{
    public static int [] concat(int[] a, int[] b) {
        int [] c = new int [a.length+b.length];
        for(int i =0; i<a.length; i++) {
            c[i] = a[i];
        }
        for(int i=0; i<b.length; i++) {
            int array = a.length;
            c[a.length + i] = b[i];
        }
        return c;
    }
    public static void print(int[] a) {
        System.out.print("[ ");
        for(int i=0; i<a.length; i++) {
            System.out.print(a[i]+" ");
        }
        System.out.print("]");
    }
}
public class StaticEx {
    public static void main(String[] args) {
        int [] array1 = { 1, 5, 7, 9 };
        int [] array2 = {3, 6, -1, 100, 77};
        int [] array3 = ArrayUtil.concat(array1, array2);
        ArrayUtil.print(array3);
    }
}
 
 

10.

package Chapter4;
import java.util.Scanner;
 
class Dictionary{
    private static String [] kor = {"사랑", "아기", "돈", "미래", "희망"};
    private static String [] eng = {"love", "baby", "money", "future", "hope"};
    public static String kor2Eng(String word) {
        int i =0;
        for(i =0; i<kor.length; i++) {
            if(word.equals(kor[i])) {
                System.out.println(word+"은 "+eng[i]);
                break;
            }
        }
        if(i == kor.length) System.out.println(word+"는 저의 사전에 없습니다.");
        return null;
    }
}
public class DicApp {
    public static void main(String[] args) {
        System.out.println("한영 단어 검색 프로그램입니다.");
        Scanner sc = new Scanner(System.in);
        Dictionary dic = new Dictionary();
        
        while(true) {
            System.out.print("한글 단어?");
            String word = sc.next();
            if(word.equals("그만")) break;
            dic.kor2Eng(word);
        }
        
        sc.close();
    }
}
 

11.

package Chapter4;
import java.util.Scanner;
 
class Add {
    private int a;
    private int b;
    public void setValue(int a, int b) {
        this.a = a;
        this.b = b;
    }
    public int calculate() {
        return this.a+this.b;
    }
}
class Sub {
    private int a;
    private int b;
    public void setValue(int a, int b) {
        this.a = a;
        this.b = b;
    }
    public int calculate() {
        return this.a-this.b;
    }
}
class Mul {
    private int a;
    private int b;
    public void setValue(int a, int b) {
        this.a = a;
        this.b = b;
    }
    public int calculate() {
        return this.a*this.b;
    }
}
class Div {
    private int a;
    private int b;
    public void setValue(int a, int b) {
        this.a = a;
        this.b = b;
    }
    public int calculate() {
        return this.a/this.b;
    }
}
public class Calculator {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("두 정수와 연산자를 입력하시오>> ");
        int a = sc.nextInt();
        int b = sc.nextInt();
        char op = sc.next().charAt(0);
        switch(op) {
        case '+':
            Add ad = new Add();
            ad.setValue(a, b);
            System.out.println(ad.calculate());
            break;
        case '-':
            Sub sb = new Sub();
            sb.setValue(a, b);
            System.out.println(sb.calculate());
            break;
        case '*':
            Mul ml = new Mul();
            ml.setValue(a, b);
            System.out.println(ml.calculate());
            break;
        case '/':
            Div dv = new Div();
            dv.setValue(a, b);
            System.out.println(dv.calculate());
            break;
        }
    }
}
 

12. 는 어려워서 넘기겠습니다 ㅎㅎ 다음에 풀게요 !!