Java第八周上机练习+作业

上机练习

1、编写一个简单程序,要求数组长度为5,分别赋值10,20,30,40,50,在控制台输出该数组的值。(知识点:数组定义和创建、一维数组初始化)[必做题]?

public class Text1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int[] a = { 10, 20, 30, 40, 50 };

        for (int i = 0; i < a.length; i++) {
            System.out.println(a[i]);

        }

    }

}

 

 2、将一个字符数组的值(neusoft)拷贝到另一个字符数组中。(知识点:数组复制) [必做题]?

public class Text2 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        char []a={'n','e','u','s','o','f','t','e','d','u','c','a','t','i','o','n'};
        char []b=new char[a.length];
        System.arraycopy(a, 0, b, 0, a.length);
        for (char c : b) {
            System.out.print(c);
        }

    }

}

 

 3、给定一个有9个整数(1,6,2,3,9,4,5,7,8)的数组,先排序,然后输出排序后的数组的值。(知识点:Arrays.sort排序、冒泡排序)

import java.util.Arrays;

import org.omg.CORBA.PRIVATE_MEMBER;


public class Text3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println("Arrays.sort排列");
        int[]a={1,6,2,3,9,4,5,7,8};
        Arrays.sort(a);
        for (int i : a) {
            System.out.print(" "+i);
        }
        System.out.println();
        System.out.println("冒泡排序");
        
        bubbleSort(a);
        System.out.println(Arrays.toString(a));
        

    }

    private static void bubbleSort(int[] a) {
        // TODO Auto-generated method stub
        for (int i = 0; i < a.length-1; i++) {
            for (int j = 0; j < a.length-1; j++) {
                if(a[j]>a[j+1]){
                    int tmp=a[j];
                    a[j]=a[j+1];
                    a[j+1]=tmp;
                }
            }
        }
        
    }

}

 

 4、 输出一个double型二维数组(长度分别为5、4,值自己设定)的值。(知识点:数组定义和创建、多维数组初始化、数组遍历)

public class Text4 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        double a[][]=new double[5][4];
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < a[i].length; j++) {
                a[i][j]=j;
            }
        }
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < a[i].length; j++) {
                System.out.print(a[i][j]+" ");                
            }
            System.out.println();
        }

    }

}

 

 5、 在一个有8个整数(18,25,7,36,13,2,89,63)的数组中找出其中最大的数及其下标。(知识点:数组遍历、数组元素访问)

public class Text5 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int x[]={18,25,7,36,13,2,89,63};
        int max=x[0],maxid=0;
        for (int i = 0; i < x.length; i++) {
            if(max<x[i]){
                max=x[i];
                maxid=i;
            }
        }
        System.out.println("最大数是:"+max+"下标为:"+maxid);

    }

}

 

 作业

1.将一个数组中的元素逆序存放(知识点:数组遍历、数组元素访问)

public class Homework1 {
 
    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a[] = { 1, 2, 3, 4, 5 };
        int b = 0;
        for (int i = 0; i < a.length / 2; i++) {
            b = a[i];
            a[i] = a[a.length - 1 - i];
            a[a.length - 1 - i] = b;
        }
        System.out.println("逆序存放为:");         
        for (int i : a) {            
            System.out.print(i);
        }
 
    }
 
}

 

2、 将一个数组中的重复元素保留一个其他的清零。(知识点:数组遍历、数组元素访问)

public class Homework2 {
 
    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a[] = {1,2,3,4,5,6,5,4,3 };
        for (int i = 0; i < a.length; i++) {
            for (int j = i + 1; j < a.length; j++) {
                if (a[i] == a[j])
                    a[j] = 0;
            }
        }
        for (int i = 0; i < a.length; i++) {
            System.out.print(a[i]+" ");         
        }
    }
 
}

 

 3、给定一维数组{ -10,2,3,246,-100,0,5},计算出数组中的平均值、最大值、最小值。(知识点:数组遍历、数组元素访问)

public class Homework3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int[] a = { -10, 2, 3, 246, -100, 0, 5 };
        int sum = 0;
        int max = a[0];
        int min = a[0];
        int b = 0;
        for (int i = 0; i < a.length; i++) {
            sum += a[i];
            if (a[i] > max)
                max = a[i];
            if (a[i] < min)
                min = a[i];
            
        }
        b = sum / 7;
        System.out.println("最大值:" + max + " 最小值:" + min + " 平均值:" + b);

   }

}

4、使用数组存放裴波那契数列的前20项 ,并输出 1 1 2 3 5 8 13 21

public class Homework4{

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int []a=new int[20];
        a[0]=1;a[1]=1;
        for(int i=2;i<a.length;i++){
            a[i]=a[i-2]+a[i-1];
        }
        System.out.println("裴波那契数列的前8项为:");
        for(int i=0;i<8;i++){
            System.out.print(a[i]+" ");
        }

   }

}

5、生成一个长度为10的随机整数数组(每个数都是0-100之间),输出,排序后,再输出

import java.util.Arrays;
import java.util.Random;
public class Homework5 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int a[] = new int[10];
        Random x = new Random();
 
        for (int i = 0; i < a.length; i++) {
            a[i] = x.nextInt(101);
        }
        System.out.println("该数组为: ");
        for (int i = 0; i < a.length; i++) {
            System.out.print(a[i]+" ");
        }
        System.out.println();
        System.out.println("排序后:  ");
        Arrays.sort(a);
        for (int i = 0; i < a.length; i++) {
            System.out.print(a[i]+" ");
        }

   }

}

 

posted @ 2021-04-26 16:56  韩世康  阅读(151)  评论(0编辑  收藏  举报