【剑指offer】表示数值的字符串

 1 class Solution {
 2 public:
 3     bool isNumeric(char* string)
 4     {
 5         if(string == NULL)    return false;
 6         if(*string == ‘+‘ || *string == ‘-‘) string++;
 7         if(*string == ‘\0‘)    return false;
 8         bool num = false, e = false, point = false;
 9         while(*string != ‘\0‘){
10             //判断数字
11             if(*string >=‘0‘ && *string <=‘9‘){
12                 num = true;
13                 string++;
14             }
15             else if(*string == ‘.‘){    //小数点
16                 if(point || e)    return false;
17                 string++;
18                 point = true;
19             }
20             else if(*string == ‘e‘ || *string == ‘E‘){    //科学计数法
21                 if(e || !num) return false;
22                 string++;
23                 e = true;
24                 if(*string == ‘+‘ || *string == ‘-‘)    string ++;
25                 if(*string == ‘\0‘)    return false;
26             }
27             else    return false;
28         }
29         return true;
30     }
31 
32 };