Luhn 算法-- 信用卡号码的校验

 1 int luhnCheck(vector<int> &digitNums)
 2 {
 3     int sz = digitNums.size();
 4     int sum = 0;
 5     for (int i=1; i <= sz; i++)
 6     {
 7         if (i%2 == 0)
 8         {
 9             int val = digitNums[sz-i] * 2;
10             if (val > 9)
11             {
12                 val -= 9;
13             }
14             sum += val;
15         }
16         else
17         {
18             sum += digitNums[sz-i];
19         }
20     }
21     cout<<"check sum: "<<sum<<endl;
22     if (sum%10 == 0)
23     {
24         return 1;
25          }
26     
27 }        return 0;