Compilare: user.cpp: In destructor ‘tractor::~tractor()’: user.cpp:31: warning: comparison between signed and unsigned integer expressions user.cpp: In member function ‘void tractor::generate_children()’: user.cpp:56: warning: comparison between signed and unsigned integer expressions user.cpp:63: warning: comparison between signed and unsigned integer expressions user.cpp:64: warning: comparison between signed and unsigned integer expressions user.cpp:71: warning: comparison between signed and unsigned integer expressions user.cpp:72: warning: comparison between signed and unsigned integer expressions user.cpp:73: warning: comparison between signed and unsigned integer expressions user.cpp:74: warning: comparison between signed and unsigned integer expressions user.cpp: In member function ‘int tractor::find(int, int)’: user.cpp:107: warning: comparison between signed and unsigned integer expressions user.cpp:110: warning: comparison between signed and unsigned integer expressions user.cpp: In member function ‘void tractor::search(int, int (*)[16])’: user.cpp:159: warning: comparison between signed and unsigned integer expressions user.cpp:162: warning: comparison between signed and unsigned integer expressions user.cpp:165: warning: comparison between signed and unsigned integer expressions user.cpp: In member function ‘void tractor::clear_M()’: user.cpp:176: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:189: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:190: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:196: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:201: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:206: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result