#include <iostream>
#include<vector>
#include<string>
using namespace std;
/*
题目描述
请实现一个函数用来判断字符串是否表示数值（包括整数和小数）。
例如，字符串"+100","5e2","-123","3.1416"和"-1E-16"都表示数值。 
但是"12e","1a3.14","1.2.3","+-5"和"12e+4.3"都不是。
*/
//判断下char是否是能使字符串是数
bool Injuge(char ch) {if (47 < ch && 58 > ch)return true;if (ch == 'e' || ch == 'E')return true;if (ch == '+' || ch == '-' || ch == '.')return true;return false;
}
class Solution {
public:bool Injuge(char ch) {if (47 < ch && 58 > ch)return true;if (ch == 'e' || ch == 'E')return true;if (ch == '+' || ch == '-' || ch == '.')return true;return false;}bool isNumeric(char* string){char* s = string;int index_e = -1;for(int i = 0; i < strlen(s); i++) {if (Injuge(s[i])) {                if (s[i] == 'e' || s[i] == 'E') {index_e = i;}}elsereturn false;}//  有e/E的情况,e/E只能出现一次//  e/E在开头结尾是falseif (index_e == 0 || index_e == strlen(s) - 1)return false;if (index_e > 0) {// 左侧 // 没有E/e情况可以按照左侧处理int num_point0 = 0;for (int i = 1; i < index_e; i++) {if (s[0] == '-' || s[0] == '+')if (s[i] == '-' || s[i] == '+')return false;if (s[0] == '.')if (s[i] == '.')return false;if (s[i] == '-' || s[i] == '+')return false;if (s[i] == '.') {num_point0++;if (num_point0 > 1)return false;}}// 右侧for (int j = index_e + 2; j < strlen(s); j++) {if (s[index_e + 1] == '.') return false;if (s[index_e + 1] == '-' || s[index_e + 1] == '+')if (s[j] == '-' || s[j] == '+')return false;if (s[j] == '.') return false;//return true;}return true;}// 没有e/E的情况else if(index_e == -1) {int num_point = 0;for (int i = 1; i < strlen(s); i++) {if (s[0] == '-' || s[0] == '+')if(s[i] == '-' || s[i] == '+')return false;if (s[0] == '.')if (s[i] == '.')return false;if (s[i] == '-' || s[i] == '+')return false;if (s[i] == '.') {num_point++;if (num_point > 1)return false;}}return true;}}};
int main() {char* str = (char*)"1.2.3 ";Solution q;cout << (bool)q.isNumeric(str) << endl;return 0;
}