“蓝桥杯”练习系统 - 基础练习 - 十六进制转十进制

注意long long

string存+反向迭代(其实没必要)

 1 #include <iostream>
 2 using namespace std;
 3 typedef long long ll;
 4 
 5 int main()
 6 {
 7     string s;
 8     cin >> s;
 9     ll ans = 0;
10     ll t = 1;
11     for (string::reverse_iterator r = s.rbegin(); r != s.rend(); r++) {
12         char x = *r;
13         ll n;
14         if (x == 'A') n = 10;
15         else if (x == 'B') n = 11;
16         else if (x == 'C') n = 12;
17         else if (x == 'D') n = 13;
18         else if (x == 'E') n = 14;
19         else if (x == 'F') n = 15;
20         else n = x - '0';
21         ans += t * n;
22         t *= 16;
23     }
24     cout << ans << endl;
25 
26     return 0;
27 }

 

posted @ 2020-03-24 17:12  域Anton  阅读(132)  评论(0)  编辑  收藏  举报