leetcode-8

题目：

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.

代码：

[java] view plain 

public class Solution {

    public int myAtoi(String str) {    //code 8
        if(str.length() == 0 || str == null)
        return 0;
        
        str = str.trim();
        int p = 0;
        double res = 0; 
        int len = str.length();
        while(str.charAt(p) == ' ' || str.charAt(p) == '\t')
        p++;
        boolean negflag = false;
        if(str.charAt(p) == '+' || str.charAt(p) == '-')
        negflag = (str.charAt(p++) == '-');
        while( p < len && (str.charAt(p) >= '0' && str.charAt(p) <= '9') ){
        res = res*10 + (str.charAt(p++) - '0');
        
        }
        res = negflag?-res:res;
        if(res > Integer.MAX_VALUE)
        return Integer.MAX_VALUE;
        if(res < Integer.MIN_VALUE)
        return Integer.MIN_VALUE;
        return (int)res;
        
    }
    
    
}