View Compilation Error

0_0_32853940_17462.cpp:2:5: error: expected unqualified-id before 'for'
     for (i=1;;i++) { if (((long long int)(n)*i-an)%M==0) break; }//https://blog.csdn.net/wukonwukon/article/details/7215467
     ^
0_0_32853940_17462.cpp:2:15: error: 'i' does not name a type
     for (i=1;;i++) { if (((long long int)(n)*i-an)%M==0) break; }//https://blog.csdn.net/wukonwukon/article/details/7215467
               ^