实现itoa()

上代码之前先讲个笑话：曾经有位面试官问：“你实现过 唉踢哦诶（音） 吗”？　　我第一个想到的是各种OA系统，心想那玩意不多是Java实现的吗。。。过一会想明白了，瞬间石化。。。

 #include <cstdio>
 #include <stdint.h>

 int8_t Myitoa(int64_t In_i64SrcNum, uint8_t In_i8Radix, char *In_pcDst)
 {
     int8_t      i8RetVal    = ;
     //这里强转是为了2、8、16进制显示的时候不需要符号
     uint64_t    ui64SrcNum  = (uint64_t)In_i64SrcNum;
     char        *pcDst      = In_pcDst;
     const char  acTable[]   = "0123456789ABCDEF";

     if (In_i8Radix <=  || pcDst == NULL)
     {
         i8RetVal = -;
         goto fun_ret;
     }

     if (ui64SrcNum == )
     {
         *(pcDst ++) = '';
         *pcDst      = ;
         goto fun_ret;
     }

     if ((int64_t)ui64SrcNum <  && In_i8Radix == )
     {
         ui64SrcNum   = ~ui64SrcNum + ;
         *(pcDst ++) = '-';
     }

     do //do...while循环的效率较高
     {
         *(pcDst ++) = acTable[ui64SrcNum % In_i8Radix];
         ui64SrcNum   /= In_i8Radix;
     } while (ui64SrcNum);
     *pcDst = ;
     pcDst --;

     In_pcDst = *In_pcDst == '-' ? In_pcDst +  : In_pcDst;
     do
     {
         char cTmp   = *In_pcDst;
         *In_pcDst   = *pcDst;
         *pcDst      = cTmp;
         In_pcDst ++;
         pcDst --;
     } while (In_pcDst < pcDst);

 fun_ret:
     return i8RetVal;
 }

 void main()
 {
     int64_t i64Test = -;
     char    acBinStr[] = {};
     char    acOctStr[] = {};
     char    acDecStr[] = {};
     char    acHexStr[] = {};
     Myitoa(i64Test, , acBinStr);
     Myitoa(i64Test, , acOctStr);
     Myitoa(i64Test, , acDecStr);
     Myitoa(i64Test, , acHexStr);
     printf("%s\n%s\n%s\n%s\n", acBinStr, acOctStr, acDecStr, acHexStr);
     return;
 }

趁着找工作这段时间，补补基础，唉，不是科班出身的短板啊。。。

参考：

http://www.cnblogs.com/applebunny/archive/2012/06/21/2557361.html

http://blog.csdn.net/wwwsq/article/details/5137006