charAt() String index out of range: 0

[Moliay]

class Solution {
    public int myAtoi(String str) {
        if(str == null || str.length() == 0){
            return 0;
        }
        
        str = str.trim();//删空格
        int flag = 1;
        int index = 0;
        int result = 0;
        
        //System.out.println(str);//no error
        
        if(str.charAt(index) == '-'){
            flag = -1;
            index ++;
        }
        else if(str.charAt(index) == '+'){
            index ++;
        }
        
        for(;index<str.length();index ++){
            if(str.charAt(index)>='9' || str.charAt(index)<='0'){
               break;
            }
            result = result*10 + (str.charAt(index) - '0');
        }
        return flag*result;
    }
}

[Moliay]

求助各位大佬

[高分子]

没有报错呀，运行
Solution so = new Solution();
int a = so.myAtoi("55667788");
System.out.println(a);

结果为

55667788

Process finished with exit code 0

[Moliay]

class Solution {
    public int myAtoi(String str) {        
        str = str.trim();//删空格
        
        if(str == null || str.length() < 1){
            return 0;
        }
        
        int flag = 1;
        int index = 0;
        long result = 0;
        
        if(str.charAt(index) == '-'){
            flag = -1;
            index ++;
        }
        else if(str.charAt(index) == '+'){
            index ++;
        }
        
        for(;index<str.length();index ++){
            int t = str.charAt(index) - '0';
            if(t>9 || t<0){
               break;
            }
            
            if(flag == 1){
                 result = result*10 + t;                
                if(result > Integer.MAX_VALUE){
                     return Integer.MAX_VALUE;
                }
            }
            else{
                result = result*10 - t;
                if(result < Integer.MIN_VALUE){
                return Integer.MIN_VALUE;
            }
         }
        }  
        
        int temp = (int)result;
        return temp;
    }
}

[Moliay]

引用 2 楼 高分子 的回复:

没有报错呀，运行
Solution so = new Solution();
int a = so.myAtoi("55667788");
System.out.println(a);

结果为

55667788

Process finished with exit code 0

谢谢猿兄的帮忙哇 当元素全为空格的元素时，会造成处理后的字符串为空哟