View Compilation Error

0_0_36589548_11647.cpp: In function 'int main()':
0_0_36589548_11647.cpp:37:35: error: 'cot' was not declared in this scope
             cout << "Case #" << ++cot << ": happy" << endl;
                                   ^
0_0_36589548_11647.cpp:40:35: error: 'cot' was not declared in this scope
             cout << "Case #" << ++cot << ": unhappy" << endl;
                                   ^