Compilare: main.cpp:3:1: warning: 'typedef' was ignored in this declaration typedef struct node ^~~~~~~ main.cpp: In function 'void read_data(const char*)': main.cpp:14:28: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fp, "%d%d", &N, &M); ^ main.cpp:23:29: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fp, "%d%d", &a, &b); ^