准完美的atoi函数实现

#include <limits.h>    #include <ctype.h>    #include <stdlib.h>     #include <stdio.h> #include <string.h>int Danny_Atoi(char *SrcString){   char *IterIndex = SrcString;   int RetVal = 0;   int SignedNegative = 1;   int int_bound = INT_MAX /10;   int Len= strlen(SrcString);   while  ( isspace( *IterIndex ) )   {       IterIndex ++;       printf("NULL SPACE...Continue....\n");        continue;   }   if ( '-' == *IterIndex )      SignedNegative  = -1;   int i =0;   while( !isdigit (*IterIndex) && int_bound && i<Len )   {      printf("Skip a non-digit: %c...\n", *IterIndex);      IterIndex ++;      i ++;   }   while ( isdigit( *IterIndex ) && int_bound )   {       printf("A digit Found:%c...\n", *IterIndex);       RetVal = RetVal*10 + (*IterIndex - '0');       int_bound/=10;       IterIndex ++;   }      if ( -1 == SignedNegative )   {      printf("The String you input is negative........\n");      RetVal*= -1;   }   if (!int_bound)    {        printf("OverFlow Number.....\n");        return -1;   }      return RetVal;}int main( int argc, char **argv ){   if (argc <= 1)   {        printf("Please Provide Your String that you want to convert....\n");        return 0;   }   int RetVal;   RetVal =  Danny_Atoi ( argv[1] );   if ( 0 == RetVal )   {printf("No Number found in the input string.....\n");   }   else if ( -1 == RetVal )   {       printf("IntGer OverFlow....\n");   }   else   {      printf("Congratulations..Number is:%d..\n", RetVal);   }         return 0;}

编译：# gcc -g -o Atoi Atoi-implementation.c

异常运行结果：

# ./Atoi
Please Provide Your String that you want to convert....

 

正常运行结果：

# ./Atoi get123get
Skip a non-digit: g...
Skip a non-digit: e...
Skip a non-digit: t...
A digit Found:1...
A digit Found:2...
A digit Found:3...
Congratulations..Number is:123..