LeeCode-String to Integer (atoi)

Implement atoi to convert a string to an integer.

Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases.

Notes: It is intended for this problem to be specified vaguely (ie, no given input specs). You are responsible to gather all the input requirements up front.

 class Solution {
 public:
     int myAtoi(string str) {
     long long cur=;
     int num=,i=;
     int flag1=,flag2=;
     while(str[i]!='\0' && str[i]==' ') i++;
     if(str[i]=='-') flag1++,i++;
     else if(str[i]=='+') flag2++,i++;
     for(; str[i]!='\0'; i++)
     {
         if(str[i]>='' && str[i]<='')
         {
             if(flag1==)
             {
                 cur=cur*-(str[i]-'');
                 if(cur<-) return -;
             }
             else if(flag1==) cur=-str[i]+'',flag1++;
             else
             {
                 cur=cur*+(str[i]-'');
                 if(cur>) return ;
             }
         }
         else break;
     }
     num=(int)cur;
     return num;
     }
 };