leetcode.008 String to Integer (atoi)

Test Instructions

Converts a string containing a number to an int type

Ideas

Implementation is not difficult, mainly considering a variety of situations.

1. string is not an empty string;

2. what to do with spaces or other characters in a string;

3. with the sign processing;

4. What to do if the number in the string exceeds the range of type int (int range:-2147483648~2147483647 0x80000000~0x7fffffff)

1 intMyatoi (Char*str) {2     intlen=strlen (str);3     intflag=1, i=0;4     Long Longans=0;5     if(len==0)6         return 0;7     Else if(len==1)8     {9         if(str[0]>='0'&& str[0]<='9')Ten             returnstr[0]-'0'; One         Else return 0; A     } -     Else -     { the         intI=0; -          while(str[i]==' ') i++;//previous empty string skipped -         if(str[i]=='-') {flag=-1; i++;} -         Else  if(str[i]=='+') {flag=1; i++;} +         Else if(str[i]>='0'&& str[i]<='9') {flag=1;} -          while(str[i]!=' /') +         { A             if(str[i]>='0'&& str[i]<='9') at             { -ans=ans*Ten+str[i]-'0'; i++; -                 if(Flag*ans>int_max) {returnInt_max; Break;} -                 Else if(flag*ans<=int_min) {returnInt_min; Break;} -             } -             Else{returnAns*flag; Break;}//If a non-numeric string is encountered, the subsequent stop scan in      -         } to         return(int) (ANS) *Flag; +     } -}

leetcode.008 String to Integer (atoi)