综合练习 学习案例
//验证码 前四位是字母 最后一位是数字
public class test1 {public static void main(String[] args){char [] chars=new char[52];for (int i = 0; i <chars.length ; i++) {if(i<=25){chars[i]=(char)(i+97);}else{chars[i]=(char)(i+65-26);}}Random r=new Random();String code="";for (int i = 0; i <4 ; i++) {int index=r.nextInt(chars.length);code+=chars[index];}code+=r.nextInt(10);System.out.println(code);}}技巧
选中 shift+f6 就可以直接修改所有的相同命名的词
抽奖
//抽奖，五个红包，顺序随机不重复，抽五次
public class test1 {public static void main(String[] args){int[] array={2,88,8888,99999,30};int[] newarray=new int[array.length];Random r=new Random();for (int i = 0; i <array.length; ) {int index=r.nextInt(array.length);boolean flag=exit(newarray,array[index]);int pri=array[index];while (!flag){newarray[i]=pri;i++;break;}}for (int i = 0; i <newarray.length ; i++) {System.out.println(newarray[i]);}}public static boolean exit(int[] newarr,int b){for (int i = 0; i <newarr.length ; i++) {if(newarr[i]==b){return true;}}return false;}}
二维数组
