Compilare: user.cpp: In function ‘void Solve_2()’: user.cpp:83:37: warning: unused variable ‘idx’ [-Wunused-variable] int i,j,ia,ib,down,up,now,A,B,C,idx; ^ user.cpp: In function ‘void Read(int&)’: user.cpp:39:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(++poz==DIM) fread(buff,1,DIM,fin),poz=0; ^ user.cpp:43:51: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(++poz==DIM) fread(buff,1,DIM,fin),poz=0; ^ user.cpp: In function ‘void Data()’: user.cpp:49:24: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d",&N); ^