View Compilation Error

0_0_17929297_1105.cpp: In function 'int main()':
0_0_17929297_1105.cpp:42:5: error: 'sg' was not declared in this scope
     sg = x;
     ^
0_0_17929297_1105.cpp:47:6: error: 'sg' was not declared in this scope
      sg = x - 1;
      ^
0_0_17929297_1105.cpp:49:6: error: 'sg' was not declared in this scope
      sg = x + 1;
      ^
0_0_17929297_1105.cpp:51:11: error: 'sg' was not declared in this scope
    res ^= sg;
           ^