Java产生随机数代码

Java产生随机数代码

//根据不同的难度产生随机字母和数字 for(int i=0; readomNumStart.length()<4; i++) { if(difficult == 1) { //产生随机的0-9的数字 a = String.valueOf((int)(Math.random() * 10)) ; } if(difficult == 2) { //在0-9和a，b，c，d中随机产生。 String[] readomWord = {"0","1","2","3","4","5","6","7","8","9","a","b","c","d"}; int readomWordIndex = (int)(Math.random() * 13); a = readomWord[readomWordIndex]; } if(difficult == 3) { //产生随机的字母 char readomLetter = (char)(Math.random ()*26+'a'); a = String.valueOf(readomLetter) ; } if(difficult == 4) { //产生随机的数字和字母的组合 String[] readomHard = new String[20]; int readomWordIndex = (int)(Math.random() * 19); for(int j=0; j<20; j++) { int readomWordNum = (int)(Math.random() * 10); char readomLetter = (char)(Math.random ()*26+'a'); if(readomWordNum % 2 == 0) { readomHard[j] = readomWordNum + ""; }else{ readomHard[j] = String.valueOf(readomLetter); } } a = readomHard[readomWordIndex]; } //

    这样写代码比较短。我也参考了许多人的代码大部分都很复杂。我不喜欢写那么多代码，所以就这样写了。还不能知道这样写效率有没有问题，在我本机上运行没有什么感觉。