Java上机操作练习题-助力期末

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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);
}
}
}