View Compilation Error

0_0_36186922_18721.cpp: In function 'int run::main()':
0_0_36186922_18721.cpp:71:19: error: 'clock' was not declared in this scope
   cerr<<1.0*clock()/CLOCKS_PER_SEC<<endl;
                   ^
0_0_36186922_18721.cpp:71:21: error: 'CLOCKS_PER_SEC' was not declared in this scope
   cerr<<1.0*clock()/CLOCKS_PER_SEC<<endl;
                     ^