Compilare: user.cpp: In function ‘void read()’: user.cpp:48:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d %d", &N, &M); ^ user.cpp:50:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d ", &val); ^ user.cpp: In function ‘void solve()’: user.cpp:58:40: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d %d %d", &op, &a, &b); ^