Compilare: user.c: In function ‘main’: user.c:21: warning: implicit declaration of function ‘strcpy’ user.c:21: warning: incompatible implicit declaration of built-in function ‘strcpy’ user.c:21: warning: implicit declaration of function ‘strlen’ user.c:21: warning: incompatible implicit declaration of built-in function ‘strlen’ user.c:11: warning: unused variable ‘n’ 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:13: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:20: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result