Eroare de compilare: user.cpp:2:15: error: math: No such file or directory user.cpp: In function ‘int prim(int)’: user.cpp:14: error: ‘sqrt’ was not declared in this scope user.cpp: In function ‘int main()’: user.cpp:20: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:21: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result