Compilare: main.cpp: In function 'void read_data()': main.cpp:23:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &k); ^ main.cpp:25:66: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] int student_id, ex_id; scanf("%d%d", &student_id, &ex_id); ^