第八次作业
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]
package apex; import java.util.Scanner; public class apex { 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(neusofteducation)拷贝到另一个字符数组中。(知识点:数组复制) [必做题]?
package apex; import java.util.Scanner; public class apex { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); String a[] = { "china" }; String b[] = new String[a.length]; System.arraycopy(a, 0, b, 0, a.length); for (String i : b) { System.out.println(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)
package apex; import java.util.Scanner; public class apex { 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; 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 apex; import java.util.Scanner; public class apex { public static void main(String[] args) { // TODO Auto-generated method stub System.out.println("矩阵是"); double[][] a = { { 1, 2, 3, 4, 5 }, { 6, 7, 8, 9, 10 }, { 11, 12, 13, 14, 15 }, { 16, 17, 18, 19, 20 } }; for (int i = 0; i < a.length; i++) { for (int j = 0; j < a[i].length; j++) { System.out.print(a[i][j] + "\t"); } 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]?
package apex; import java.util.Scanner; public class apex { public static void main(String[] args) { // TODO Auto-generated method stub int[] a = { 18, 25, 7, 36, 13, 2, 89, 63 }; int max = a[0]; for (int i = 0; i < a.length; i++) { if (max < a[i]) { max = a[i]; } } System.out.println("最大值为:" + max); } }
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) [选作题]•
package apex; import java.util.Scanner; public class apex { 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
package apex; import java.util.Scanner; public class apex { public static void main(String[] args) { // TODO Auto-generated method stub int []a={1,1,2,2,3,3,4,4,5,5}; for(int i=0;i<a.length;i++){ System.out.print(a[i]+" "); } System.out.println(); System.out.println("重复项清零"); for(int j=0;j<a.length;j++){ for(int k=j+1;k<a.length;k++){ if(a[j]==a[k]) a[k]=0; } } for(int j=0;j<a.length;j++){ System.out.print(a[j]+" "); } } }
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)
package apex; import java.util.Scanner; public class apex { public static void main(String[] args) { // TODO Auto-generated method stub int []x={-10,2,3,246,-100,0,5}; double sum=0; for(double y:x){ sum+=y; } double z=sum/x.length; System.out.println("平均数是"+z); } }
4.使用数组存放裴波那契数列的前20项 ,并输出
package apex; import java.util.Scanner; public class apex { public static void main(String[] args) { // TODO Auto-generated method stub int[] a = new int[20]; a[0] = 1; int x = 1; int y = 1; int z = 1; for (int i = 1; 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]); } } }
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
package apex; import java.util.Random; import java.util.Scanner; public class apex { public static void main(String[] args) { // TODO Auto-generated method stub Random random = new Random(10); int a[] = new int[10]; for (int i = 0; i < a.length; i++) { a[i] = random.nextInt(200); System.out.print(" "+a[i]); } System.out.println(); 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; } } } System.out.println(); for (int i = 0; i < a.length; i++) { System.out.print(" " + a[i]); } } }