[Leetcode] Valid Number

 1 class Solution {
 2 public:
 3     bool isNumber(const char *s) {
 4         while (*s == ‘ ‘) ++s;
 5         while (*s == ‘+‘ || *s == ‘-‘) ++s;
 6         bool exp = false, space = false, point = false;
 7         bool number = false;
 8         while (*s != ‘\0‘) {
 9             if (isdigit(*s)) {
10                 if (space) return false;
11                 else number = true;
12             } else if (*s == ‘.‘) {
13                 if (!point && !space && !exp) {
14                     point = true;
15                 } else {
16                     return false;
17                 }
18             } else if (*s == ‘e‘) {
19                 if (!exp && number && !space) {
20                     exp = true;
21                     number = false;
22                     while (*(s+1) == ‘+‘ || *(s+1) == ‘-‘) ++s;
23                 } else {
24                     return false;
25                 }
26             } else if (*s == ‘ ‘) {
27                 if (!space) {
28                     space = true;
29                 }
30             } else {
31                 return false;
32             }
33             ++s;
34         }
35         return number;
36     }
37 };