Compilare: user.cpp: In function ‘void query(int, int, int, int)’: user.cpp:64:9: warning: unused variable ‘i’ [-Wunused-variable] int i,x; ^ user.cpp:64:11: warning: unused variable ‘x’ [-Wunused-variable] int i,x; ^ user.cpp: In function ‘char nextch()’: user.cpp:13:31: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf,1,MAXBUF,fi); ^