View Compilation Error

0_0_38602359_28841.cpp: In function 'bool isPrime(int)':
0_0_38602359_28841.cpp:10:23: error: 'sqrt' was not declared in this scope
  for (int i = 2; i <= sqrt(n); i++)
                       ^~~~
0_0_38602359_28841.cpp:10:23: note: suggested alternative: 'qsort'
  for (int i = 2; i <= sqrt(n); i++)
                       ^~~~
                       qsort