用C++实现：将16进制转换为10进制

 1 #include<iostream>
 2 #include<cmath>
 3 #include<cstring>
 4 using namespace std;
 5 int main(void)
 6 {
 7     int n;
 8     int temp;
 9     char* arr = new char[9];       //要给‘\0’留一位
10     cin >> arr;
11     n = strlen(arr);               //计算字符串长度
12     long long sum = 0;             //用long long防止结果过大
13     for (int i = 0; arr[i]!=‘\0‘; i++)         //最后一位是‘\0‘，不用算进去
14     {
15         switch (arr[i])
16         {
17         case ‘A‘: temp = 10; break;
18         case ‘B‘: temp = 11; break;
19         case ‘C‘: temp = 12; break;
20         case ‘D‘: temp = 13; break;
21         case ‘E‘: temp = 14; break;
22         case ‘F‘: temp = 15; break;
23         default: temp = arr[i] - ‘0‘; break;
24         }
25         sum = sum + temp * pow(16, n - 1- i);
26     }
27     cout << sum;
28     return 0;
29 }