Valid Number

class Solution {
public:
    bool isNumber(string s) 
    {
        const int n = s.size();
        int i = 0;
        while(i < n && s[i] == ' ')
            ++i;
        if(i == n)
            return false;
        if(s[i] == '+' || s[i] == '-')
            ++i;
            
        int numofpoint=0;
        int numofdigit=0;
        while(s[i] == '.' || s[i] >= '0' && s[i] <= '9')
        {
            if(s[i] == '.')
                ++numofpoint;
            else
                ++numofdigit;
            ++i;
        }
        if(numofpoint > 1 || numofdigit < 1)
            return false;
        if(s[i] == 'e')
        {
            ++i;
            if(s[i] == '-' || s[i] == '+')
                ++i;
            int numofdigit1=0;
            while(s[i]>='0' && s[i] <= '9')
            {
                ++numofdigit1;
                ++i;
            }    
            if(numofdigit1<1)
                return false;
        }
        
        while(i<n)
        {
            if(s[i]==' ')
                ++i;
            else
                break;
        }
        if(i == n)
            return true;
        else
            return false;
        
        
    }
};