View Compilation Error

0_0_21005574_29130.cpp: In function 'int main()':
0_0_21005574_29130.cpp:7:34: error: 'scanf_s' was not declared in this scope
  while (scanf_s("%d%d%d",&a,&b,&n), a || b || n) //遍历肯定超时，打表不现实，数据太大，只有找规律啦！！！
                                  ^