Eroare de compilare: user.c:2:16: error: cmath: No such file or directory user.c: In function ‘main’: user.c:10: warning: implicit declaration of function ‘sqrt’ user.c:10: warning: incompatible implicit declaration of built-in function ‘sqrt’ user.c:6: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:7: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:9: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result