View Compilation Error

0_0_34672926_19219.cpp: In function 'int main()':
0_0_34672926_19219.cpp:125:30: error: 'log2' was not declared in this scope
    else cost = -log2(1 - cost);
                              ^
0_0_34672926_19219.cpp:140:37: error: 'pow' was not declared in this scope
   printf("%.2lf\n", 1 - pow(2, -cost));
                                     ^