实验3-方法和数组

x x x x大学计算机与信息技术学院for(int i=0;i<list.length;i++){System.out.print(" "+list[i]); //输出已排序数组}}}运行结果贴图：2.插入排序import java.util.*;public class LX3_2 {public static void main(String[] args) {double []text={ 7, 4, 3, 9, 0, 6};insertionSort(text);}public static void insertionSort(double [] list){for(int i=1;i<list.length;i++){double currentElement=list[i]; //找见现在排序的元素int k;for(k=i-1;k>=0&&list[k]>currentElement;k--){list[k+1]=list[k]; //移动出插入位置}list[k+1]=currentElement; //放入插入数据}for(int i=0;i<list.length;i++){System.out.print(" "+list[i]); //输出已排序数组}}}运行结果贴图：3冒泡排序import java.util.*;public class LX3_3 {public static void main(String[] args) {double []text={ 7, 4, 3, 9, 0, 6};Sort(text);}public static void Sort(double [] list){for(int i=0;i<list.length;i++){for(int j=list.length-1;j>i;j--){ //length-1 length超出围if(list[j]<list[j-1]){double t=list[j];list[j]=list[j-1];list[j-1]=t;}}}System.out.println("排序结果是：");for(int i=0;i<list.length;i++){System.out.print(" "+list[i]); //输出已排序数组}}}‘运行结果贴图:（2）编写程序实现两个矩阵的相加、相乘。

要求程序运行结果形如如下显示：Array c1 2 34 5 67 8 9Array d2 2 21 1 13 3 3Array c+d3 4 55 6 710 11 12Array c*d13 13 1331 31 3149 49 49for (int i = 0; i < 3; i++) {for (int j = 0; j < 3; j++) {Answer[i][j] = cheng1[i][0] * cheng2[0][j] + cheng1[i][1]* cheng2[1][j] + cheng1[i][2] * cheng2[2][j];}}shuChu(Answer);}}运行结果贴图:（3）将用“；”和“，”分割的包含数字字符的字符串“23,21.3,33；34,2,1.9,2.1；3,3,1,3,4,4.9”中的数据解析出来放在一个double类型的二维数组中，以分号分割二维数组的每一行，以逗号分割每行中的各个元素。

（利用String 的split方法）程序代码：（4）查看帮助、编写例子利用System类中的arraycopy()方法复制数组。

分别用Arrays类中的sort方法和binarySearch方法实现数组的排序和折半查找。

程序代码：1.复制数组：public class LX3_6 {public static void main(String[] args) {int[] old = { 1, 2, 3, 4, 5, 6, 7 };int[] copy = new int[7];System.arraycopy(old, 0, copy, 0, old.length);// TODO Auto-generated method stubfor (int i = 0; i < copy.length; i++) {System.out.println(copy[i]);}}}运行结果贴图：2.数组排序：import java.util.*;public class LX3_7 {public static void main(String[] args) { double[] te = { 7, 4, 3, 9, 0, 6 };Arrays.sort(te); // 多种方法重载for (int i = 0; i < te.length; i++) {System.out.println(te[i]);}}}运行结果贴图：3.折半查找：import java.util.*;public class LX3_8 {public static void main(String[] args) {double[] te = { 1, 9, 21, 31, 44, 56, 78, 99 };System.out.println("请输入要查找的数");Scanner input = new Scanner(System.in);int i = input.nextInt();System.out.println(Arrays.binarySearch(te, i));}}运行结果贴图:（5）随机生成100个小写字母，统计每个字母出现的次数，并显示出来。

（利用Math.random()方法随机产生）程序代码：public class LX3_9 {public static void main(String[] args) {char[] number = new char[100];for (int i = 0; i < number.length; i++) {number[i] = (char) ('a' + Math.random() * ('z' - 'a' + 1));}CountNumber(number);}public static void CountNumber(char[] Count) {int[] counts = new int[26];for (int i = 0; i < Count.length; i++) {counts[Count[i] - 'a']++; //count字符减字符存到相应的位置}SystemOut(counts);}public static void SystemOut(int[] syso) {for (int i = 0; i < syso.length; i++) {System.out.println((char) (i + 'a') + "出现的次数是：" + syso[i]);//i对应a~z }}}运行结果贴图:（6）建立一个不规则的二维数组如下，并在控制台显示，数组如下1 3 52 4 6 81 9 16 25 3610 20 301 2 3 4 5 6程序代码：public class LX3_10 {public static void main(String[] args) {int[][] new1 = { { 1, 3, 5 }, { 2, 4, 6, 8 }, { 1, 9, 16, 25, 36 }, { 10, 20, 30 }, { 1, 2, 3, 4, 5, 6 } };for (int i = 0; i < 5; i++) {for (int j = 0; j < new1[i].length; j++) {System.out.printf("%-4d", new1[i][j]);}System.out.println();}}}运行结果贴图:（7）编写两个重载的方法分别交换两个整型变量，和整型数组的第一个和第二个元素，运行并分析结果程序代码：public class LX3_11 {public static void main(String[] args) {int a = 2, b = 5;int[] c = { 2, 5};Switch(a, b);Switch(c);}public static void Switch(int a, int b) {int t;t = a;a = b;b = t;System.out.println("交换以后：");System.out.println("a=" + a + " b=" + b);}public static void Switch(int[] a) {int t;t = a[0];a[0] = a[1];a[1] = t;System.out.println("a[0]=" + a[0] + " a[1]=" + a[1]);}}运行结果贴图:课后作业题P153 5.16 5.23 5.25P184 6.13P186 6.26P202 7.1 7.2 7.6 7.23*5.16程序代码：public class LX3_12 {public static void main(String[] args) {for (int i = 2000; i <= 2010; i++) {System.out.println(i + "年的天数是" + numberOfDaysInYear(i));}}public static int numberOfDaysInYear(int year) {if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) { return 366;} else {return 365;}}}运行结果贴图：5.23程序代码：public class LX3_13 {public static void main(String[] args) {System.out.println("100个大写字母：");SysOut('A', 'Z');System.out.println("100个一位数：");SysOut('0', '9');}public static char getRandomCharacter(char ch1, char ch2) { return (char) (ch1 + Math.random() * (ch2 - ch1 + 1));}public static void SysOut(char zf1, char zf2) {for (int i = 0; i < 10; i++) {for (int j = 0; j < 10; j++) {System.out.printf("%-4c", getRandomCharacter(zf1, zf2));}System.out.println();}}}运行结果贴图：5．25程序代码：import java.util.*;public class LX3_14 {public static void main(String[] args) {Scanner input = new Scanner(System.in);System.out.println("请输入毫秒数：");long i = input.nextLong();System.out.println(convertMillis(i));}public static String convertMillis(long mills) {long a = mills / 3600000;long b = (mills - a * 3600000) / 60000;long c = (mills - a * 3600000 - b * 60000) / 1000;return (a + ":" + b + ":" + c); /* 转换为String类型 1.i+"空或字符串"; 2 String.valueOf(i);*/}}运行结果贴图：6.13程序代码：public class LX3_15 {public static void main(String[] args) {int[] a = { 1, 4, 13, 51 };System.out.println(getRandom(a));}public static int getRandom(int... numbers) { int s = (int) (1 + Math.random() * 54);for (int i = 0; i < numbers.length; i++) { int a = numbers[i] - s;if (a == 0) {s = getRandom(numbers);}}return s;}}运行结果贴图：7.1程序代码：import java.util.*;public class LX3_17 {/*** param args*/public static void main(String[] args) {System.out.println("Enter a 4-by-4 matrix now by row:");System.out.println("Sun of the matrix is " + add(creatArrays()));}public static int[][] creatArrays() {int[][] array1 = new int[4][4];Scanner input = new Scanner(System.in);for (int i = 0; i < 4; i++) {for (int j = 0; j < 4; j++) {array1[i][j] = input.nextInt();}}return array1;}public static int add(int[][] list) { int sum = 0;for (int i = 0; i < 4; i++) {for (int j = 0; j < 4; j++) {sum = sum + list[i][j];}}return sum;}}运行结果贴图：7.2程序代码：7.6程序代码：import java.util.Scanner;public class LX3_19 {/*** param args*/public static void main(String[] args) {System.out.print("Enter matrix1:");double[][] array1 = creatArrays();System.out.print("Enter matrix2:");double[][] array2 = creatArrays();double[][] array3 = Cheng(array1, array2);System.out.println("The matrices are multiplied as follows:");sysOut(array1, array2, array3);// TODO自动生成的方法存根}}return Answer;}}运行结果贴图：7.23程序代码：import java.util.*;public class LX3_20 {public static void main(String[] args) {double[][] arrayText = creatArrays();double su = 1 / count1(arrayText);double[][] arrayText2 = array2(arrayText);double[][] arrayText3 = array3Count(arrayText2, su);print(arrayText3);}}return arry3;}public static void print(double[][] list4) {for (int i = 0; i < 3; i++) {for (int j = 0; j < 3; j++) {System.out.printf("%2g ", list4[i][j]);}System.out.println();}}}运行结果贴图：。