题解 | #把字符串转换成整数#

#include <string>
class Solution {
public:
    int StrToInt(string str) {
        int ans=0;
        int cnt=0;
        if(str[0]=='+')
            str.erase(0, 1);
        for(int i=str.size()-1;i>=0;i--)
        {
            if((str[i]>='0'&&str[i]<='9')||str[i]=='-')
            {
                if(str[i]=='-')
                    return -ans;
                ans=(str[i]-'0')*pow(10,cnt++)+ans;
            }
            else
               return 0;
        }
        return ans;
    }
};