表示数值的字符串

#include <iostream>
#include <type_traits>
using namespace std;

class Solution
{
    public:
        bool is_numberic(string s);
        bool scan_integer(string::iterator &it);
        bool scan_unsigned_integer(string::iterator &it);
};
bool Solution::is_numberic(string s) 
{
    if(s.empty())
        return false;
    
    auto it=s.begin(); 
    bool num=scan_integer(it);
    
    if(*it==‘.‘)
    {
        ++it;
        num=scan_unsigned_integer(it)||num;
    }
    if(*it==‘e‘||*it==‘E‘)
    {
        ++it;
        num=num&&scan_integer(it);
    }
    return num&&*it==‘\0‘;
}
bool Solution::scan_integer(string::iterator &it)
{
    if(*it==‘+‘||*it==‘-‘)
        ++it;
    return scan_unsigned_integer(it);
}
bool Solution::scan_unsigned_integer(string::iterator &it)
{
    string::const_iterator i=it;
    while(*it!=‘\0‘&&*it>=‘0‘&&*it<=‘9‘)
        ++it;
    return it>i?true:false;
}
int main()
{
    string s;
    cin>>s;
    Solution S;
    cout<<S.is_numberic(s)<<endl;
    return 0;
}