View Compilation Error

0_0_31091513_29232.cpp: In function 'll& qadd(ll&, ll)':
0_0_31091513_29232.cpp:5:57: error: expected ';' before '}' token
 ll &qadd(ll &a, ll b){return a += b, a >= M ? a -= M : a};
                                                         ^
0_0_31091513_29232.cpp: In function 'void ITT(ll*, ll)':
0_0_31091513_29232.cpp:51:7: error: 'i' was not declared in this scope
  for (i = 0; i < len; i++)
       ^