JavaSE_数组_十进制转其他进制

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查表法

package uncommitted;public class WeekTest {public static void main(String[] args) {// 查表法练习!String week=method(41);System.out.println(week);}public static String method(int i) {// 用查表法根据数字查星期几!//增强健壮性检查if(i>7||i<0){return "wrong number";}String[] arr={"","星期1","星期2","星期3","星期4","星期5","星期6","星期天"};return arr[i];}}

NumberTransfer1

package uncommitted;public class NumberTransfer {public static void main(String[] args) {// 进制转换toHex(60);}   private static void toHex_4(int num) {// 查表法3终极版本_2      if(num==0){         System.out.println("0");         return;      }            char[] arr={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};            char[] cha=new char[8];      //因为前面说过,int是四字节,      //1字节有8个二进制位,所以共计32个二进制位!      //转成16进制是4位一取,所以最多要取8次!            int pos=cha.length-1;//从数组最后面开始存!            while(num!=0){               int temp=num&15;//15就是二进制里1111               //根据索引查出十六进制中对应的字符!               cha[pos--]=arr[temp];               //四位一取               num=num>>>4;            }            //因为是pos--,所以下标多减了一次,要加回来!            pos=pos+1;            for (int i = pos; i <cha.length; i++) {//打印数组的有效位!               System.out.print(cha[i]);            }            //传入60,对应的结果是3C         }   private static void toHex_3(int num) {// 查表法3终极版本_1      char[] arr={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};      char[] cha=new char[8];      //因为前面说过,int是四字节,1字节有8个二进制位,      //所以共计32个2进制位!转成16进制是4位一取,所以最多要取8次!      int pos=0;//操作数组就会乃至指针!      while(num!=0){         int temp=num&15;//15就是二进制里1111         cha[pos]=arr[temp];         pos++;         num=num>>>4;//四位一取      }      for (int i = pos-1; i >=0; i--) {//打印新数组的有效位,从后面往前打印!         System.out.print(cha[i]);      }               //传入60,对应的结果是3C   }      private static void toHex_2(int num) {      // 查表法2    需要改进      char[] arr={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};      char[] cha=new char[8];      //因为前面说过,int是四字节,1字节有8个二进制位,      //所以共计32个2进制位!转成16进制是4位一取,所以最多要取8次!      int pos=0;//操作数组就会乃至指针!      while(num!=0){         int temp=num&15;//15就是二进制里1111         cha[pos]=arr[temp];         pos++;         num=num>>>4;      }      for (int i = 0; i < pos; i++) {//打印数组的有效位!         System.out.print(cha[i]);      }      //传入60,对应的结果却是C3 还需要改进,逆序~   }      private static void toHex_1(int num) {      //查表法1       char[] arr={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};      for (int i = 0; i < 8; i++) {         if(num==0){            break;         }         int temp=num&15;         System.out.print(arr[temp]);         //直接打印是:倒着的,要先存起来,再逆序输出~         num=num>>>4;      }   }   public static void toHex(int num){//      int是4个字节,1个字节有8个二进制位,共有32个二进制位//      转16进制是4位一取,所以最多要移动8次      for (int i = 0; i < 8; i++) {         int temp=num&15;         if(temp==0)            continue;         if (temp>9) {            System.out.print((char)(temp-10+'A'));         } else {            System.out.print(temp);         }         num=num>>>4;      }   }}

NumberTransfer2

package uncommitted;public class NumberTransfer2 {   public static void main(String[] args) {      // 最牛X的进制转换函数      toHex(60);      toBinary(6);      toBinary('帅');      toOctal(60);      System.out.println(Integer.toBinaryString(-6));      System.out.println(Integer.toBinaryString('帅'));      System.out.println(Integer.toHexString(15));      System.out.println(Integer.toOctalString(60));//   int  -6的二进制表示:1111-1111    1111-1111   1111-1111   1111-1010   }   public static void toHex(int num){      transfer(num, 16, 4);//16进制,要与上15,四位一移   }   public static void toBinary(int num){      transfer(num, 2, 1);//2进制,要与上1,一位一移   }   public static void toOctal(int num){      transfer(num, 8, 3);//8进制,要与上7,三位一移   }   private static void transfer(int num,int base,int offset) {      int source=num;      if(num==0){         System.out.println("0");         return;      }      char[] arr={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};      char[] cha=new char[32];//因为前面说过,int是四字节,1字节有//8个二进制位,所以共计32个2进制位!      int pos=cha.length;//从数组最后面开始存!      while(num!=0){         int temp=num&(base-1);//15就是二进制里1111         cha[--pos]=arr[temp];         num=num>>>offset;      }      System.out.print(source+"对应的"+base+"进制数是:  ");      for (int i = pos; i <cha.length; i++) {//打印数组的有效位!         System.out.print(cha[i]);      }      System.out.println();   }         private static void transfer_toHex(int num) {      if(num==0){         System.out.println("0");         return;      }      char[] arr={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};      char[] cha=new char[8];      //因为前面说过,int是四字节,1字节有8个二进制位,      //所以共计32个2进制位!转成16进制是4位一取,所以最多要取8次!      int pos=cha.length;//从数组最后面开始存!      while(num!=0){         int temp=num&15;//15就是二进制里1111         cha[--pos]=arr[temp];         num=num>>>4;      }      for (int i = pos; i <cha.length; i++) {//打印数组的有效位!         System.out.print(cha[i]);      }   }}

NumberTransfer3

package uncommitted;public class NumberTransfer3 {   public static void main(String[] args) {      transfer(60,8);      System.out.println(Integer.toBinaryString(-6));      System.out.println(Integer.toBinaryString('帅'));      System.out.println(Integer.toHexString(15));      System.out.println(Integer.toOctalString(60));   }   public static void transfer(int num,int base) {      int source=num;      if(num==0){         System.out.println("0");         return;      }      int offset;      switch (base) {         case 16://16进制,要与上15,四位一移            offset=4;            break;         case 8://8进制,要与上7,三位一移            offset=3;            break;         case 2://2进制,要与上1,一位一移            offset=1;            break;      default:         offset=1;         break;      }      char[] arr={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};      char[] cha=new char[32];      //因为前面说过,int是四字节,1字节有8个二进制位,      //所以共计32个2进制位!转成16进制是4位一取,所以最多要取8次!      int pos=cha.length;//从数组最后面开始存!      while(num!=0){         int temp=num&(base-1);//15就是二进制里1111         cha[--pos]=arr[temp];         num=num>>>offset;      }      System.out.print(source+"对应的"+base+"进制数是:  ");      for (int i = pos; i <cha.length; i++) {//打印数组的有效位!         System.out.print(cha[i]);      }      System.out.println();   }   private static void transfer_toHex(int num) {      if(num==0){         System.out.println("0");         return;      }      char[] arr={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};      char[] cha=new char[8];      //因为前面说过,int是四字节,1字节有8个二进制位,      //所以共计32个2进制位!转成16进制是4位一取,所以最多要取8次!      int pos=cha.length;//从数组最后面开始存!      while(num!=0){         int temp=num&15;//15就是二进制里1111         cha[--pos]=arr[temp];         num=num>>>4;      }      for (int i = pos; i <cha.length; i++) {//打印数组的有效位!         System.out.print(cha[i]);      }   }}

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