Compilare: user.cpp: In function ‘int main()’: user.cpp:147:14: warning: unused variable ‘ok’ [-Wunused-variable] bool ok = 1; ^ user.cpp: In function ‘void read_query()’: user.cpp:85:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &card); ^ user.cpp:89:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp: In function ‘int main()’: user.cpp:122:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &N, &M, &K); ^