Leetcode 8 String to Integer (string to int)

Title Source: https://leetcode.com/problems/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 don't see below and ask yourself what is the possible input cases.

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

Update (2015-02-10):
The signature of the C++ function had been updated. If you still see your function signature accepts a const char * argument, please click on the reload button to reset your code Definition.

Problem Solving Ideas:

Write the code according to the requirements, can be summarized as follows:

1. String is empty or all spaces, return 0;

2. Prefix spaces for strings need to be ignored;

3. After ignoring the prefix space, the first character encountered, if it is ' + ' or '-', continue reading, if it is a number, start processing the number, if not the previous 2, return 0;

4. In the process of processing numbers, if the subsequent characters printable numbers, stop the conversion and return the current value;

5. In the above process, if the converted value is outside the range of type int, the maximum or minimum value of int is returned.

Java code:

1  Public classSolution {2      Public intmyatoi (String str) {3         intMax =Integer.max_value;4         intMin =-Integer.min_value;5         Longresult = 0;6str =Str.trim ();7         intLen =str.length ();8         if(Len < 1)9             return0;Ten         intStart = 0; One         BooleanNeg =false; A   -         if(Str.charat (start) = = '-' | | Str.charat (START) = = ' + ') { -             if(Str.charat (start) = = '-') theNeg =true; -start++; -         } -   +          for(inti = start; i < Len; i++) { -             CharCH =Str.charat (i); +   A             if(Ch < ' 0 ' | | ch > ' 9 ') at                  Break; -result = Ten * result + (CH-' 0 ')); -             if(!neg && Result >max) -                 returnMax; -             if(Neg &&-result <min) -                 returnmin; in   -         } to         if(neg) +result =-result; -   the         return(int) result; *     } $  Panax Notoginseng};

Leetcode 8 String to Integer (string to int)