【美团~牛客】十六进制转十进制

 1 // 16_10jinzhi.cpp : 定义控制台应用程序的入口点。
 2 //
 3
 4 #include "stdafx.h"
 5 #include<iostream>
 6 #include<string>
 7 #include<math.h>
 8 using namespace std;
 9
10
11 int getNum(char c)
12 {
13     int temp = 0;
14     switch(c)
15     {
16     case ‘A‘:
17         temp = 10;
18         break;
19     case ‘B‘:
20         temp = 11;
21         break;
22     case ‘C‘:
23         temp = 12;
24         break;
25     case ‘D‘:
26         temp = 13;
27         break;
28     case ‘E‘:
29         temp = 14;
30         break;
31     case ‘F‘:
32         temp = 15;
33         break;
34     case ‘0‘:
35         temp = 0;
36         break;
37     case ‘1‘:
38         temp = 1;
39         break;
40     case ‘2‘:
41         temp = 2;
42         break;
43     case ‘3‘:
44         temp = 3;
45         break;
46     case ‘4‘:
47         temp = 4;
48         break;
49     case ‘5‘:
50         temp = 5;
51         break;
52     case ‘6‘:
53         temp = 6;
54         break;
55     case ‘7‘:
56         temp = 7;
57         break;
58     case ‘8‘:
59         temp = 8;
60         break;
61     case ‘9‘:
62         temp = 9;
63         break;
64     }
65     return temp;
66 }
67
68 int _tmain(int argc, _TCHAR* argv[])
69 {
70     string OX_num;
71     while(cin>>OX_num)
72     {
73         int len =  OX_num.length();
74         if(len <= 2)
75             return -1;
76         int result = 0;
77         for(int i = 2; i < len;i++)
78         {
79             int temp = 0;
80             if((OX_num[i]>=‘A‘ && OX_num[i] <= ‘F‘)||    (OX_num[i]>=‘0‘ && OX_num[i] <= ‘9‘) )
81                 temp = getNum(OX_num[i]);
82             else
83                 return -1;
84
85             result += temp*(pow(static_cast<double>(16),len - i - 1));
86         }
87         cout<<result<<endl;
88     }
89     return 0;
90 }