Compilare: user.cpp: In function ‘int main()’: user.cpp:41:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qmatrix.in","r",stdin); ^ user.cpp:42:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qmatrix.out","w",stdout); ^ user.cpp:44:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d\n", &n, &x, &y, &q); ^ user.cpp:73:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c %d %d\n", &chr, &k, &p); ^