将数字从基数10转换为N.

这段代码是我必须开发的项目的一部分。 我需要编写一个java方法，将一个数字（基数为10）转换为n base中的另一个数字。 这是该类的代码：

 public class converter { public int from_10_to_n(int base, int newbase) { int k = 0; String res = ""; String output = ""; do { //Below I explain what I'm doing here base /= newbase; k = base % newbase; res += String.valueOf(k); } while (base != 0); for(int i=res.length()-1; i>-1; i--) { output += res.charAt(i); } return Integer.parseInt(output); } 

我想以这种方式制作程序：

do {} while(); 循环划分数字并将剩余部分保存在k中。 然后我创建一个for循环来反转字符串res（它有提醒）。

顺便说一句，当我在我的主要方法中调用该方法时，我错过了最后一位数字。 我的意思是：

 converter k = new converter(); int e = k.from_10_to_n(a /*base 10 number*/, b /*Base n number*/); System.out.println(a+" -> "+b+" is " + e); 

使用此代码，如果我想将231转换为base 4，则结果为321而不是3213 。 我检查了我的代码，但我找不到解决方案。 任何想法？

我和其他基地有同样的错误。 例如31（基数10）是11111 （基数2）但我的程序返回1111 。

Answer 1

翻转循环中前两行的顺序; 通过先做分裂，你会失去第一个余数。 但是你需要处理最后的剩余部分。

Answer 2

问题在于：

 base /= newbase; k = base % newbase; 

尝试使用一些实数，例如231和base 4。

 base /= newbase 

现在base为57，你的k将是不正确的。 你应该先得到余数，然后除以：

 k = base % newbase; base /= newbase; 

您的代码也存在一些样式问题，您应该考虑纠正：

• base并不真正拥有任何基础，只是输入值 – 可能将其重命名为input或类似的东西？
• 混合缩进。 你的循环缩进一个空格，而其余的代码有四个。

Answer 3

我们的十进制系统的字母表是“0123456789”。 现在，基数为N的任意字母数字系统的字母表是“＃0＃1＃2＃…＃9＃10＃11＃…＃1234＃… #N”所以，总结一下，简化，为输出添加兼容性并进行测试：

 /* * Program FromBase10ToBaseN * This program receives as input * a positive integer number in base 10 * and outputs its encoding in arbitrary base N. * The k-th symbol of the new base is denoted #k. * Tests are provided. * Jose (2016) * evoljava.com */ package Programs; import java.util.Random; public class FromBase10ToBaseN { private static final Random RANDOM = new Random(); public static void main(String[] args) throws Exception { //Number in base 10 int inputValue = 9; //New base int N = 10; reportFromBase10ToBaseN(inputValue, N); inputValue = 100; N = 10; reportFromBase10ToBaseN(inputValue, N); inputValue = 8; //New base N = 2; reportFromBase10ToBaseN(inputValue, N); inputValue = 129; //New base N = 128; reportFromBase10ToBaseN(inputValue, N); inputValue = 127; //New base N = 128; reportFromBase10ToBaseN(inputValue, N); //test with random numbers for (int i = 0; i < 10; i++) { inputValue = RANDOM.nextInt(1000); //New base must be 2 or greater N = 2 + RANDOM.nextInt(80); reportFromBase10ToBaseN(inputValue, N); } } private static void reportFromBase10ToBaseN(int inputValue, int N) { String outputValue = fromBase10ToBaseN(inputValue, N); int Backwards = fromBaseNToBase10(outputValue, N); String isRight = "wrong"; if (inputValue == Backwards) isRight = "right"; System.out.println(inputValue + " in base 10 becomes " + outputValue + " in base " + N + " Backwards: " + Backwards + " " + isRight); } private static String fromBase10ToBaseN(int inputValue, int N) { String res ; String outputValue = ""; do { res = "#" + String.valueOf(inputValue % N); outputValue = res + outputValue; inputValue /= N; } while (inputValue != 0); return outputValue; } //The input string denotes a number in base newBase //The k-th symbol of the new base is denoted #k. //Example: #10#0 in base 15 represents 150 in base 10 private static int fromBaseNToBase10(String inputValue, int N) { if (inputValue.charAt(0) == '#') { int outputValue = 0; boolean correct = true; int length = inputValue.length(); String token = ""; int power = 0; //Tokenizing: //Exmpl: #1#120#13#2 is separated into tokens 1 120 13 2 for (int i = length - 1; (i > -1) & correct; i--) { char c = inputValue.charAt(i); if (c != '#') { token = c + token; } else { //tokens are evaluated int p = Integer.parseInt(token); //Detecting the presence of an alien symbol if (p >= 0) { outputValue = (int) (outputValue + p * Math.pow(N, power)); power++; } else { outputValue = -1; correct = false; } token = ""; } } return outputValue; } else return -1; } }//End of Program FromBase10ToBaseN OUTPUT: 9 in base 10 becomes #9 in base 10 Backwards: 9 right 100 in base 10 becomes #1#0#0 in base 10 Backwards: 100 right 8 in base 10 becomes #1#0#0#0 in base 2 Backwards: 8 right 129 in base 10 becomes #1#1 in base 128 Backwards: 129 right 127 in base 10 becomes #127 in base 128 Backwards: 127 right 382 in base 10 becomes #6#40 in base 57 Backwards: 382 right 390 in base 10 becomes #11#5 in base 35 Backwards: 390 right 788 in base 10 becomes #3#1#4 in base 16 Backwards: 788 right 285 in base 10 becomes #3#4#6 in base 9 Backwards: 285 right 68 in base 10 becomes #1#31 in base 37 Backwards: 68 right 656 in base 10 becomes #24#8 in base 27 Backwards: 656 right 442 in base 10 becomes #9#28 in base 46 Backwards: 442 right 765 in base 10 becomes #21#30 in base 35 Backwards: 765 right 455 in base 10 becomes #10#35 in base 42 Backwards: 455 right 211 in base 10 becomes #4#3 in base 52 Backwards: 211 right