java第八次作业
1编写一个简单程序,要求数组长度为5,静态赋值10,20,30,40,50,在控制台输出该数组的值。
package home; public class jiatingzuoye { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int []a={10,20,30,40,50}; for (int i : a) { System.out.println(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)
package home; public class jiatingzuoye { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub String[] a = { "java" }; String[] b = new String[a.length]; System.arraycopy(a, 0, b, 0, a.length); for (String string : b) { System.out.println(string); } } }
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)
package home; public class jiatingzuoye { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int a[] = { 1, 6, 2, 3, 9, 4, 5, 7, 8 }; for (int i = 0; i < a.length - 1; i++) { for (int j = 0; j < a.length - 1 - i; j++) { if (a[j] > a[j + 1]) { int temp = a[j]; a[j] = a[j + 1]; a[j + 1] = 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)
package home; public class jiatingzuoye { /** * @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; } } System.out.println("二维数组为"); 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
package home; public class jiatingzuoye { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int[] a = new int[] { 1, 2, 3, 4, 1, 2, 5, 7 }; int max = a[0]; int min = 0; for (int i = 0; i < a.length; i++) { if (a[i] > max) { max = a[i]; min = i; } } System.out.println("下标:" + min); System.out.println("最大值:" + max); } }
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]
package home; public class jiatingzuoye { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int []a={1,2,3,4,5,6,7,8,9}; for(int x=0;x<9;x++){ System.out.print(a[x]+" "); } System.out.println(); for (int y=8;y>=0;y--){ System.out.print(a[y]+" "); } } }
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)
package home; public class jiatingzuoye { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int[] a = { 1, 2, 2, 3, 3, 3, 4,4 }; 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; } } } for (int i = 0; i < a.length; i++) { System.out.println(a[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)
package home; public class jiatingzuoye { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int []a={ -10,2,3,246,-100,0,5}; int max = a[0],min = a[0]; double sum = 0; for (int i = 1; i < a.length; i++) { if (a[i] > max) { max = a[i]; } if (a[i] < min) { min = a[i]; } } for (int i = 0; i < a.length; i++) { sum += a[i]; } System.out.println("最大值为" + max); System.out.println("最小值为" + min); System.out.println("平均值为" + sum / a.length); } }
9、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
package home; public class jiatingzuoye { /** * @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-1]+a[i-2]; } for (int i = 0; i < 8; 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
package home; import java.util.Arrays; import java.util.Random; public class jiatingzuoye { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int l[] = new int[10]; Random x = new Random(); for (int i = 0; i < l.length; i++) { l[i] = x.nextInt(101); } for (int i = 0; i < l.length; i++) { System.out.println(l[i]); } System.out.println("排序后: "); Arrays.sort(l); for (int i = 0; i < l.length; i++) { System.out.println(l[i]); } } }