Java语言程序设计基础篇编程练习题-第一章

不念不忘少年蓝@ 2022-12-05 13:50 169阅读 0赞

### 1.1（显示三条消息） ###

public class Test1_01 {
        
    	public static void main(String[] args) {
        
    		System.out.println("Welcome to Java");
    		System.out.println("Welcome to Computer Science");
    		System.out.println("Programming is fun");
    	}
    }

### 1.2（显示五条消息） ###

public class Test1_02 {
        
    	public static void main(String[] args) {
        
    		int num = 5;
    		for(int i = 0; i < num; i++) {
        
    			System.out.println("Welcome to Java");
    		}
    	}
    }

### 1.3（显示图案） ###

public class Test1_03 {
        
    	public static void main(String[] args) {
        
    		System.out.println("    J    A    V     V    A");
    		System.out.println("    J   A A    V   V    A A");
    		System.out.println("J   J  A   A    V V    A   A");
    		System.out.println(" J J  A     A    V    A     A");
    	}
    }

### 1.4（打印表格） ###

public class Test1_04 {
        
    	public static void main(String[] args) {
        
    		System.out.println("a\ta^2\ta^3");
    		int num = 4;
    		for(int i = 1; i <= num; i++) {
        
    			System.out.println(i + "\t" + (i * i) + "\t" + (i * i * i));
    		}
    	}
    }

### 1.5（计算表达式） ###

public class Test1_05 {
        
    	public static void main(String[] args) {
        
    		double num = (8.5 * 4.5 - 2.5 * 3) / (45.5 - 3.5);
    		System.out.println(num);
    	}
    }

### 1.6（数列求和） ###

public class Test1_06 {
        
    	public static void main(String[] args) {
        
    		int num_start = 1;
    		int num_end = 9;
    		int sum = 0;
    		for(int i = num_start; i <= num_end; i++) {
        
    			sum += i;
    		}
    		System.out.println(sum);
    	}
    }

### 1.7（近似求p） ###

public class Test1_07 {
        
    	public static void main(String[] args) {
        
    		int num_end1 = 11;
    		int num_end2 = 13;
    		System.out.println(computer(num_end1));
    		System.out.println(computer(num_end2));
    	}
    	public static double computer(int num_end) {
        
    		double sum = 0;
    		for(int i = 1, n = 0; i <= num_end; i += 2, n++) {
        
    			sum += 1.0/(i * Math.pow(-1, n));
    		}
    		double number = 4 * sum;
    		return number;
    	}
    }

### 1.8（圆的面积和周长） ###

public class Test1_08 {
        
    	private static final double PI = 3.1415926;
    	public static void main(String[] args) {
        
    		double radius = 5.5;
    		System.out.println("area is " + getArea(radius));
    		System.out.println("perimeter is " + getPerimeter(radius));
    	}
    	public static double getArea(double radius) {
        
    		return radius * radius * PI;
    	}
    	public static double getPerimeter(double radius) {
        
    		return 2 * radius * PI;
    	}
    }

### 1.9（矩形的面积和周长 ） ###

public class Test1_09 {
        
    	public static void main(String[] args) {
        
    		double height = 7.9;
    		double width = 4.5;
    		System.out.println("area is " + getArea(height, width));
    		System.out.println("perimeter is " + getPerimeter(height, width));
    	}
    	public static double getArea(double height, double width) {
        
    		return height * width;
    	}
    	public static double getPerimeter(double height, double width) {
        
    		return 2 * (height + width);
    	}
    }

### 1.10（以英里计的平均速度） ###

public class Test1_10 {
        
    	public static void main(String[] args) {
        
    		double kil = 14;
    		double mil = 1.6 * kil;
    		int time = 45 * 60 + 30;
    		double hour = time / 3600.0;
    		System.out.println(mil/hour + "英里/小时");
    	}
    }

### 1.11（人口估算） ###

public class Test1_11 {
        
    	public static void main(String[] args) {
        
    		int num = 312032486;
    		for(int i = 1; i <= 5; i++) {
        
    			num = fun(i, num);
    			System.out.println("第" + i + "年的人口数是： " + num);
    		}
    	}
    	public static int fun(int i, int num) {
        
    		int time = 3600 * 24 * 365 * i;
    		double birth = time / 7.0;
    		double die = time / 13.0;
    		double in = time / 45.0;
    		int change = (int) (birth + in - die);
    		num += change;
    		return num;
    	}
    }

### 1.12（以公里计的平均速度） ###

public class Test1_12 {
        
    	public static void main(String[] args) {
        
    		double mil = 24;
    		double kil = mil / 1.6;
    		int time = 1 * 3600 + 40 * 60 + 35;
    		double hour = time / 3600.0;
    		System.out.println(kil/hour + "公里/小时");
    	}
    }

### 1.13（代数，求解2\*2线性方程） ###

public class Test1_13 {
        
    	public static void main(String[] args) {
        
    		double a = 3.4, b = 50.2, e = 44.5, c = 2.1, d = 0.55, f = 5.9;
    		double x = (e * d - b * f) / (a * d - b * c);
    		double y = (a * f - e * c) / (a * d - b * c);
    		System.out.println("x = " + x + "\ty=" + y);
    	}
    }

以上代码均为个人编写，不当之处，悉请指正。