View Compilation Error

0_0_36404919_28630.cpp: In function 'int main()':
0_0_36404919_28630.cpp:154:49: error: 'clock' was not declared in this scope
     cout << "The run time is:" << (double)clock() /CLOCKS_PER_SEC<< "s" << endl;
                                                 ^
0_0_36404919_28630.cpp:154:52: error: 'CLOCKS_PER_SEC' was not declared in this scope
     cout << "The run time is:" << (double)clock() /CLOCKS_PER_SEC<< "s" << endl;
                                                    ^