View Compilation Error

0_0_15686028_13357.cpp: In function 'int main()':
0_0_15686028_13357.cpp:34:17: error: 'clock' is not a member of 'std'
 const auto t0 = std::clock();
                 ^
0_0_15686028_13357.cpp:36:33: error: 'memset' was not declared in this scope
         memset(mem,-1,sizeof mem);
                                 ^
0_0_15686028_13357.cpp:42:16: error: 'clock' is not a member of 'std'
   while (1000*(std::clock() - t0) / CLOCKS_PER_SEC < 3000)
                ^
0_0_15686028_13357.cpp:42:37: error: 'CLOCKS_PER_SEC' was not declared in this scope
   while (1000*(std::clock() - t0) / CLOCKS_PER_SEC < 3000)
                                     ^