View Compilation Error

0_0_20470704_7475.cpp:85:3: error: expected unqualified-id before 'return'
   return (res+MOD) % MOD;
   ^
0_0_20470704_7475.cpp:86:2: error: expected ';' after struct definition
  }
  ^
0_0_20470704_7475.cpp: In member function 'long long int Matrix::det(int, long long int)':
0_0_20470704_7475.cpp:70:17: error: 'i' was not declared in this scope
    for (int j = i+1; j < n; j++) 
                 ^
0_0_20470704_7475.cpp:83:20: error: 'i' was not declared in this scope
    res = res * mat[i][i] % MOD;
                    ^
0_0_20470704_7475.cpp: At global scope:
0_0_20470704_7475.cpp:87:1: error: expected declaration before '}' token
 }ret;
 ^