/*** @Description 颠倒数组排列顺序* @author SEELE* @date 2017年8月17日 上午10:56:17* @action sortArr*/public static void sortArr() {int[] b = new int[6];int[] a = { 1, 2, 3, 4, 5, 6, 7 };for (int i = 0; i < a.length / 2; i++) {int temp = a[a.length - 1 - i];a[a.length - 1 - i] = a[i];a[i] = temp;}System.out.println(Arrays.toString(a));}/*** @Description 判读一个数是否是素数* @author SEELE* @date 2017年8月17日 上午11:00:02* @action sushu*/public static void sushu() {int N = 17;if (N < 2) {System.out.println("不是素数");}for (int i = 2; i * i <= N; i++) {if (N % i == 0) {System.out.println("不是素数");return;}}System.out.println("是素数");}/*** @Description 计算平方根，牛顿迭代法* @author SEELE* @date 2017年8月17日 上午11:16:17* @action sqrt* @param c* @return*/public static double sqrt(double c) {if (c < 0) {return Double.NaN;}double err = 1e-15;double t = c;while (Math.abs(t - c / t) > err * t) {t = (c / t + t) / 2.0;}return t;}/*** @Description （自写）二分查找，先做一个从小到大的数组排序* @author SEELE* @date 2017年8月17日 下午2:33:52* @action erfenfind*/public static void erfenfind() {int[] a = { 54, 54, 56, 56, 78, 8, 3232, 56, 546, 546, 46, 7854, 12, 3255, 58, 678, 585, 23, 45, 3, 6, 8, 89,6 };System.out.println(Arrays.toString(a));int find = 8;Arrays.sort(a);System.out.println(Arrays.toString(a));int lo = 0;int hi = a.length - 1;while (lo <= hi) {int mid = lo + (hi - lo) / 2;if (find > a[mid]) {lo = mid + 1;} else if (find < a[mid]) {hi = mid - 1;} else {System.out.println(mid + "---" + a[mid]);break;}}}/*** 将一个正整数的转换成二进制，并已字符串打印出来*/public static void binaryString() {long N = 5646753274687L;String s = "";for (long n = N; n > 0; n /= 2)s = (n % 2) + s;System.out.println(s);}/*** 1.1.13 编写一段代码，打印出一个M 行N 列的二维数组的转置（交换行和列）。*/public static void MNtoNM() {int b = 0;int m = 10;int n = 3;int[][] a = new int[m][n];for (int i = 0; i < a.length; i++) {for (int j = 0; j < a[i].length; j++) {a[i][j] = b;b++;}}for (int[] is : a) {for (int i : is) {System.out.print(i+" ");}System.out.println();}int[][] c = new int[n][m];for(int i=0;i<n;i++)  {  for(int j=0;j<m;j++)  {  c[i][j] = a[j][i];  }  }  System.out.println("-----------分割------------");  for (int[] is : c) {for (int i : is) {System.out.print(i+" ");}System.out.println();}}