Java第八次上机作业
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]•
import java.util.Scanner; public class homework1 { public static void main(String[] args) { 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(neusofteducation)拷贝到另一个字符数组中。(知识点:数组复制) [必做题]•
import java.util.Arrays; import java.util.Scanner; public class homework2 { public static void main(String[] args) {char a[] = {'j','a','v','a' };
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 (int i = 0; i < b.length; i++) { System.out.print(b[i]); } } }
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.Scanner; public class homework3 { /** * @param args */ public static void main(String[] args) { //冒泡排序 int [] a = {1,6,2,3,9,4,5,7,8}; for (int i = 0; i < a.length; i++) { for (int j = i; j < a.length; j++) { //相邻交换 if (a[i] > a[j]){ int temp = a[i]; a[i] = a[j]; a[j] = temp; } } } for (int i : a){ System.out.println(i); } } }
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)
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) [必做题]•
import java.util.Scanner; public class homework5 { /** * @param args */ public static void main(String[] args) { int [] a = {18,25,7,36,13,2,89,63}; int max = 0; int min = 0; int maxdx = 0; int mindx = 0; for (int i = 0; i < a.length; i++) { if(a[i]>max){ max = a[i]; maxdx = i; } if(a[i]<min){ min = a[i]; mindx = i; } } System.out.println("最大的的数是"+max+"下标是"+maxdx); } }
作业
6、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) [选作题]•
import java.util.Scanner;
public class homework6 {
public static void main(String[] args) { // 6、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) [选作题]•
Scanner input=new Scanner(System.in);
int []a=new int[5];
for (int i = 0; i < a.length; i++) {
a[i]=input.nextInt();
}
System.out.println("逆序存放后的数组为");
for (int i = a.length; i >0 ; i--) {
System.out.println(a[i-1]);
}
}
}
7. 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) [选作题]课后作业•
import java.util.Scanner; public class homework7 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("数组中元素为"); int []a=new int[6]; for (int i = 0; i < a.length; i++) { a[i]=input.nextInt(); } for (int i = 0; i < a.length; i++) { for (int j = 0; j < a.length; j++) { if(a[i]==a[j]&&i!=j) a[j]=0; } } System.out.println("重复元素清零后为"); for (int i : a) { System.out.print(i+" "); } } }
8、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)
import java.util.Arrays; public class homework8 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub // 8、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) int a[] = { -10, 2, 3, 246, -100, 0, 5 }; int max = a[0], min = a[0]; int sum = 0; double avg = 0; for (int i = 0; i < a.length; i++) { sum += a[i]; avg = sum / 7; if (a[i] > max) { max = a[i]; } if (a[i] < min) { min = a[i]; } } System.out.println("平均值为" + avg); System.out.println("最大值为" + max); System.out.println("最小值为" + min); } }
9、使用数组存放裴波那契数列的前20项 ,并输出
public class homework9 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub // 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 int a[] = new int[20]; a[0] = 1; int x = 1; int y = 1; int z = 1; for (int i = 0; i < a.length; i++) { a[i] = z; z = x + y; x = y; y = z; } for (int i = 0; i < a.length; i++) { System.out.println(a[i]); } } }
10、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 homework10 { public static void main(String[] args) { // TODO Auto-generated method stub // 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 Random r = new Random(); int a[] = new int[10]; for (int i = 0; i < a.length; i++) { a[i] = r.nextInt(100); System.out.println(a[i]); } Arrays.sort(a); System.out.println("排序后输出"); for (int i = 0; i < a.length; i++) { System.out.println(a[i]); } } }