View Compilation Error

0_0_38635836_12250.cpp: In function 'int largestPrimeFactor(int)':
0_0_38635836_12250.cpp:14:17: error: 'sqrt' was not declared in this scope
     int limit = sqrt(n / 2);
                 ^~~~
0_0_38635836_12250.cpp:14:17: note: suggested alternative: 'qsort'
     int limit = sqrt(n / 2);
                 ^~~~
                 qsort