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1. 运行时输入一个数n， 求1+2!+3!+…+n!的和；

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		int add = facadd(n);
		System.out.println(add);
	}

	public static int facadd(int n) {
		int sum = 0;
		for (int i = 1; i <= n; i++) {
			int ret = 1;
			for (int j = 1; j <= i; j++) {
				ret *= j;
			}
			sum += ret;
		}
		return sum;
	}

2. 使用for循环打印九九乘法表；

public static void main(String[] args) {
		for (int i = 1; i <= 9; i++) { 
			for (int j = 1; j <= i; j++) {
				int sum = i * j;
				System.out.print(j + "*" + i + "=" + sum + "" + "\t");
			}
			System.out.println();
		}
}

3. 编写一个应用程序求100以内的全部素数；

	public static void main(String args[]) {
		int i, j;
		for (i = 2; i <= 100; i++) {
			for (j = 2; j <= i / 2; j++) {
				if (i % j == 0)
					break;
			}
			if (j > i / 2) {
				System.out.println("" + i + "是素数");
			}
		}
	}

4. 请实现对一整型数序列的排序操作算法（冒泡）；

	public static int[] bubbleSort(int[] array) {
		if (array.length == 0)
			return array;
		for (int i = 0; i < array.length; i++)
			for (int j = 0; j < array.length - 1 - i; j++)
				if (array[j + 1] < array[j]) {
					int temp = array[j + 1];
					array[j + 1] = array[j];
					array[j] = temp;
				}
		return array;
	}
}

5. 使用面向对象思想编写猜数字游戏：

一个类A有一个成员变量v，设置一个随机初值。
定义一个类，对A类的成员变量v进行猜。
如果大了则提示大了，小了则提示小了。等于则提示猜测成功。

public class TestE {
	class A {
		int v = (int) (Math.random() * 10);

		public int getV() {
			return v;
		}

		public void setV(int v) {
			this.v = v;
		}

	}

	class B {
		int c = (int) (Math.random() * 10);
		A a = new TestE().new A();

		void guss() {
			if (c > a.getV()) {
				System.out.println("猜大了");
			} else if (c == a.getV()) {
				System.out.println("成功");
			} else {
				System.out.println("猜小了");
			}
		}
	}

	public static void main(String[] args) {
		B b = new TestE().new B();
		b.guss();
	}
}

6. 已知猫类和狗类：

属性:毛的颜色,腿的个数
行为:吃饭
猫特有行为:抓老鼠catchMouse
狗特有行为:看家lookHome
利用面向对象继承法来做

package four;

public class Animal {
	String color;
	int leg;
	
	public String getColor() {
		return color;
	}

	public void setColor(String color) {
		this.color = color;
	}

	public int getLeg() {
		return leg;
	}

	public void setLeg(int leg) {
		this.leg = leg;
	}

	@Override
	public String toString() {
		return "Dog [color=" + color + ", leg=" + leg + "]";
	}

	void eat() {
		System.out.println("吃饭");
	}

}

Cat

public class Cat {
	void catchMouse() {
		System.out.println("抓老鼠");
	}
}

Dog

public class Dog {
	void lookHome() {
		System.out.println("看家");
	}
}

7. 编写一个程序，用于输出起始部分如下的Fibonacci数列1，1，2，3，5，8，13，21，34，55

public class TestF {
	public static long fibonacci(long number) {
		if ((number == 0) || (number == 1))
			return number;
		else
			return fibonacci(number - 1) + fibonacci(number - 2);
	}

	public static void main(String[] args) {
		for (int counter = 0; counter <= 10; counter++) {
			System.out.printf("Fibonacci of %d is: %d\n", counter, fibonacci(counter));
		}
	}
}

8. 编写程序输入5学生的姓名和年龄并打印出来，同时求出平均年龄

Student

package four;

public class Student {
	
	private String name;
	private int age;
	
	public Student() {
	}

	public Student(String name, int age) {
		this.name = name;
		this.age = age;
	}

	public String getName() {
		return name;
	}

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

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public String toString() {
		return "Student [name=" + name + ", age=" + age + "]";
	}
	
}

StudentMain

public class StudentMain {
	public static void main(String[] args) {
		Student[] myStu = new Student[5];
		for (int i = 0; i < 5; i++) {
			myStu[i] = new Student();
		}
		Scanner sc = new Scanner(System.in);
		for (int i = 0; i < 5; i++) {
			System.out.println("请输入第" + (i + 1) + "个学生的姓名");
			String s = sc.nextLine();
			myStu[i].setName(s);
		}
		for (int i = 0; i < 5; i++) {
			System.out.println("请输入第" + (i + 1) + "个学生的年龄");
			String s = sc.nextLine();
			int a = Integer.parseInt(s);
			myStu[i].setAge(a);
		}
		for (int i = 0; i < 5; i++) {
			System.out.println("第" + (i + 1) + "个学生的姓名是" + myStu[i].getName() + ",年龄是" + myStu[i].getAge());
			System.out.println("平均年龄" + (myStu[0].getAge() + myStu[1].getAge() + myStu[2].getAge() + myStu[3].getAge()
					+ myStu[4].getAge()) / 5);
		}
	}
}