题解 | #整数与IP地址间的转换#

#include <iostream>
#include <cmath>
#include <string>
using namespace std;

int main() {
  	//ch的使用又让我长见识了
    char ch;
    string res_str;
    long ip_num, res;
    unsigned int n1, n2, n3, n4;
    cin >> n1 >> ch >>n2>>ch>>n3>>ch>>n4;
    cin>>ip_num;
    res = n1*pow(2, 8*3) + n2*pow(2, 8*2)+ n3*pow(2, 8) + n4;
    cout << res <<endl;

    res_str += to_string((ip_num>>24)&0xff) + ".";
    res_str += to_string((ip_num>>16)&0xff) + ".";
    res_str += to_string((ip_num>>8)&0xff) + ".";
    res_str += to_string(ip_num&0xff);
    cout << res_str << endl;
}
// 64 位输出请用 printf("%lld")