Java部分答案.doc

2.1 (Y. Daniel Liang英文版八版 P232：6.16) (Execution time) Write a program that randomly generates an array of 100000 integers and a key. Estimate the execution time of invoking the linearSearch method in Listing 6.6. Sort the array and estimate the execution time of invoking the binarySearch method in Listing 6.7. You can use the following code template to obtain the execution time: long startTime = System.currentTimeMillis(); perform the task; long endTime = System.currentTimeMillis(); long executionTime = endTime - startTime; 2.2 (Y. Daniel Liang英文版八版 P232：6.17 ) (Revising selection sort) In§6.10.1, you used selection sort to sort an array. The selection-sort method repeatedly finds the smallest number in the current array and swaps it with the first number in the array. Rewrite this program by finding the largest number and swapping it with the last number in the array. Write a test program that reads in ten double numbers, invokes the method, and displays the sorted numbers. 然后使用java.util.Arrays类的排序方法，并进行对比。 2.3 (Y. Daniel Liang英文版八版 P232： 6.19) (Sorting students) Write a program that prompts the user to enter the number of students, the students’ names, and their scores, and prints student names in decreasing order of their scores. 2.4 (Y. Daniel Liang英文版八版 P233：6.27 Identical arrays) Two arrays list1 and list2 are identical if they have the same contents. Write a method that returns true if list1 and list2 are identical, using the following header: public static boolean equal(int[] list1, int[] list2) Write a test program that prompts the user to enter two lists of integers and displays whether the two are identical. Here are the sample runs. Note that the first number in the input indicates the number of the elements in the list. //6.16 package foundation; import java.util.*; class home{ public static int LinearSearch(int[] list, int key){ for(int i=0;ilist.length;i++){ if(key == list[i]) return i; } return -1; } } public class homework1 { publ