Compilare: user.cpp: In function ‘int main()’: user.cpp:21: warning: comparison between signed and unsigned integer expressions user.cpp:11: warning: unused variable ‘output’ user.cpp:16: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp:17: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp:20: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result