题解 | IP地址

#include<bits/stdc++.h>
using namespace std;

int a[4] = {256, 256, 256, 256};

int main(){
  	//scanf格式化读取即可
    while(scanf("%d.%d.%d.%d", a, a+1, a+2, a+3)!=EOF){
        bool flag = false;
        for(int i=0; i<4; ++i){
            if(a[i]<0 || a[i]>255) {
                flag = true;
                break;
            }
            a[i] = 256;
        }
        if(flag) cout<<"No!\n";
        else cout<<"Yes!\n";
    }
    return 0;
}