Compilare: user.cpp: In function ‘int main()’: user.cpp:27:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&n,&m); ^ user.cpp:29:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d " ,&x); ^ user.cpp:34:47: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d %d %d " ,&t,&a,&b,&k); ^ user.cpp:64:61: warning: ‘first’ may be used uninitialized in this function [-Wmaybe-uninitialized] s.insert({val, b - a + 1, x1.sp + b - a + 1}); ^