【java】第3章选择测试题（作业部分）

淩亂°似流年 2022-11-07 14:56 118阅读 0赞

### 文章目录 ###

*   *  3.15
     *  3.22
     *  3.27
     *  3.28
     *  3.29

## 3.15 ##

![在这里插入图片描述][20210313081119512.png]

//3.15 (3-8改）
    import java.util.Scanner;
    public class Demo {
        
    
    	public static void main(String[] args) {
        
    		Scanner input = new Scanner(System.in); 
    		System.out.print("Enter your lottery pick: ");
    		int guess = input.nextInt();
    //		int lottery = (int)(Math.random() * 900 + 100);
    		int lottery = 456;
    		int lo = lottery, gu = guess;
    		System.out.println("The lottery number is " + lottery);
    		int l[] = new int[4], g[] = new int[4]; 
    		l[1]= lo / 100; g[1] = gu / 100;
    		lo %= 100; gu %= 100;
    		l[2] = lo / 10; g[2] = gu / 10;
    		l[3] = lo % 10; g[3] = gu % 10;
    		boolean flag = false;
    		for(int i = 1; i <= 3; i++){
        
    			for(int j = 1; j <= 3; j++){
        
    				if(l[i] == g[j]){
        
    					flag = true;
    					break;
    				}
    			}
    			if(flag)
    				break;
    		}
    		if(guess == lottery)
    			System.out.println("Exact match: you win $10,000");
    		else if(l[1] == g[1] && l[2] == g[3] && l[3] == g[2] ||
    			    l[1] == g[2] && l[2] == g[1] && l[3] == g[3] ||
    			    l[1] == g[2] && l[2] == g[3] && l[3] == g[1] ||
    			    l[1] == g[3] && l[1] == g[1] && l[3] == g[2] ||	
    			    l[1] == g[3] && l[2] == g[2] && l[3] == g[1])
    			System.out.println("Match all digit: you win $3,000");
    		else if(flag)
    			System.out.println("Match one digit: you win $1,000");
    		else
    			System.out.println("Sorry, no match");			
    	}
    
    }
    /*
    123
    132
    213
    231
    312
    321
    */

## 3.22 ##

![在这里插入图片描述][20210313081150395.png]

//3.22
    import java.util.Scanner;
    public class Demo {
        
    
    	public static void main(String[] args) {
        
    		Scanner input = new Scanner(System.in);
    		System.out.print("Enter a point with two coordinates: ");
    		double x = input.nextDouble();
    		double y = input.nextDouble();
    		if(Math.sqrt((x * x + y * y)) <= 10)
    			System.out.print("Point (" + x + ", " + y + ") is in the circle" );
    		else
    			System.out.print("Point (" + x + ", " + y + ") is not in the circle" );
    	}
    
    }

## 3.27 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1ODc4Mjky_size_16_color_FFFFFF_t_70]

//3.27
    import java.util.Scanner;
    public class Demo {
        
    
    	public static void main(String[] args) {
        
    		Scanner input = new Scanner(System.in);
    		System.out.print("Enter a point's x- and y- coordinates: ");
    		double x = input.nextDouble(), y = input.nextDouble();
    		if(100 - 0.5 * x - y >= 0 && x >= 0 && y >= 0)
    			System.out.print("The point is in the triangle");
    		else
    			System.out.print("The point is not in the triangle");
    		
    	}
    
    }
    
    /*
    y = 100 - 0.5 * x
    y = 0
    x = 0
    */

## 3.28 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1ODc4Mjky_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][20210313111657733.png]

//3.28
    import java.util.Scanner;
    public class Demo {
        
    
    	public static void main(String[] args) {
        
    		Scanner input = new Scanner(System.in);
    		System.out.print("Enter r1's center x-, y-coordinates, width, and height: ");
    		double x1 = input.nextDouble(), y1 = input.nextDouble(), 
    			   w1 = input.nextDouble(), h1 = input.nextDouble(),
    			   lx1 = x1 - w1 / 2, ly1 = y1 + h1 / 2,
    		       rx1 = x1 + w1 / 2, ry1 = y1 - h1 / 2;
    		System.out.print("Enter r2's center x-, y-coordinates, width, and height: ");
    		double x2 = input.nextDouble(), y2 = input.nextDouble(), 
    			   w2 = input.nextDouble(), h2 = input.nextDouble(),
    			   lx2 = x2 - w2 / 2, ly2 = y2 + h2 / 2,
    			   rx2 = x2 + w2 / 2, ry2 = y2 - h2 / 2;
    		if(lx1 <= lx2 && ly1 >= ly2 && rx1 >= rx2 && ry1 <= ry2)
    			System.out.println("r2 is inside r1");
    		else if(lx1 <= rx2 && ly1 >= ry2 && rx1 >= lx2 && ry1 <= ly2)
    			System.out.println("r2 overlaps r1");
    		else
    			System.out.println("r2 does not overlap r1");
    	}
    
    }

## 3.29 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1ODc4Mjky_size_16_color_FFFFFF_t_70 2]

//3.29
    import java.util.Scanner;
    public class Demo {
        
    
    	public static void main(String[] args) {
        
    		Scanner input = new Scanner(System.in);
    		System.out.print("Enter circle1's center x-, y-coordinates, and tadius: ");
    		double x1 = input.nextDouble(), y1 = input.nextDouble(), r1 = input.nextDouble();
    		System.out.print("Enter circle1's center x-, y-coordinates, and tadius: ");
    		double x2 = input.nextDouble(), y2 = input.nextDouble(), r2 = input.nextDouble();
    		double squareOfDistance = (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1);
    		if(squareOfDistance <= (r1 - r2) * (r1 - r2))
    			System.out.println("circle2 is inside circle1");
    		else if(squareOfDistance <= (r1 + r2) * (r1 + r2))
    			System.out.println("circle2 overlaps circle1");
    		else
    			System.out.println("circle2 does not overlap circle1");
    		
    	}
    
    }

[20210313081119512.png]: /images/20221023/8905333bab8549c197d75c517d03e22b.png
[20210313081150395.png]: /images/20221023/ae7da8a3ba004c759803a2fed024a4d5.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1ODc4Mjky_size_16_color_FFFFFF_t_70]: /images/20221023/20bd7b72c01a497e87112dc55fcdd4ef.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1ODc4Mjky_size_16_color_FFFFFF_t_70 1]: /images/20221023/489b4135a206447590af0233b9d95d1c.png
[20210313111657733.png]: /images/20221023/edf96ad52def4725a2b4f0875b8b0373.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1ODc4Mjky_size_16_color_FFFFFF_t_70 2]: /images/20221023/15ff5dd0c9d34221a19b38f93f2dc75a.png