View Compilation Error

0_0_31498703_21788.cpp: In function 'long long int pcf::Lehmer(long long int)':
0_0_31498703_21788.cpp:52:19: error: 'sqrt' was not declared in this scope
   s = sqrt(0.9 + m), y = c = cbrt(0.9 + m);
                   ^
0_0_31498703_21788.cpp:52:42: error: 'cbrt' was not declared in this scope
   s = sqrt(0.9 + m), y = c = cbrt(0.9 + m);
                                          ^
0_0_31498703_21788.cpp: At global scope:
0_0_31498703_21788.cpp:59:12: error: expected constructor, destructor, or type conversion before ';' token
 pcf::init();
            ^
0_0_31498703_21788.cpp:60:7: error: expected constructor, destructor, or type conversion before '(' token
 printf("%lld\n",pcf::Lehmer(n));
       ^