Compilare: user.cpp:2:9: warning: #pragma once in main file [enabled by default] #pragma once ^ user.cpp: In function ‘int main()’: user.cpp:969:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &n); ^ user.cpp:974:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%llu%llu", &op, &c); ^