Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:45:34: warning: format ‘%lu’ expects argument of type ‘long unsigned int*’, but argument 3 has type ‘int*’ [-Wformat=] fscanf(fread, "%lu", &opt); ^ user.cpp:60:21: error: ‘f’ was not declared in this scope fprintf(f, "%d", exists); ^ user.cpp:41:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fread, "%lu", &nrOperatii); ^ user.cpp:45:35: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fread, "%lu", &opt); ^ user.cpp:46:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fread, "%lu", &nr); ^