Compilare: user.cpp: In function ‘int main()’: user.cpp:62:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mxl.in", "r", stdin); ^ user.cpp:63:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mxl.out", "w", stdout); ^ user.cpp:65:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ user.cpp:69:32: 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 member function ‘void String::Read()’: user.cpp:24:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", a); ^ user.cpp: In member function ‘int String::Calculate_cell()’: user.cpp:53:50: warning: ‘last’ may be used uninitialized in this function [-Wmaybe-uninitialized] answer += M[last][nr].Calculate_cell(); ^