题目链接:https://leetcode-cn.com/problems/string-to-integer-atoi/
题目如下:
class Solution {
public:
int myAtoi(string s) {
if(s.size()==0) return 0;
s.erase(0,s.find_first_not_of(' '));
if(isdigit(s[0]==false&&s[0]!='+'&&s[0]!='-')) return 0;
int flag=1,i=0;
if(s[0]=='+') i++;
else if(s[0]=='-') {
flag=-1;i++;}
long long result=0;
for(;i<s.size();i++){
if(isdigit(s[i])) result=result*10+s[i]-'0';
else break;
if(flag==1&&result>=INT_MAX) return INT_MAX;
else if(flag==-1&&-result<=INT_MIN) return INT_MIN;
}
return result*flag;
}
};