题解 | #IP地址#

#include<cstdio>
#include<string>
#include<iostream>
using namespace std;
int main() {
	string str;
	getline(cin, str);
	int flag = 1;
	string result;
	for (int i = 0; i < str.size(); i++) {
		if (str[i] == '.' ) {
			if (stoi(result) > 255 || stoi(result) < 0) {
				flag = 0;
				break;
			}
			else {
				result = "";
			}
		}
		else {
			result += str[i];
		}
	}
	if (stoi(result) > 255 || stoi(result) < 0)
		flag = 0;
	if (flag == 1)
		printf("Yes!");
	else
		printf("No!");
}