Compilare: user.cpp: In function ‘void read()’: user.cpp:19: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:21: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void df(int, int)’: user.cpp:34: warning: comparison between signed and unsigned integer expressions user.cpp:31: warning: unused variable ‘st’ user.cpp:31: warning: unused variable ‘dr’ user.cpp: In function ‘void write()’: user.cpp:71: warning: comparison between signed and unsigned integer expressions user.cpp:74: warning: comparison between signed and unsigned integer expressions