香八方汤烤锅王加盟之c++mini幻灯片.ppt

* * * * Answer: To avoid circular includes, use forward declarations * Minimize compile dependency. Speeds up compilation. (don’t need to recompile every time gui.H changes) * * Discuss make/makefiles Errors can occure in any of the three above mentioned units… * * Much like a java reference (but more explicit) A pointer is a variable that contains the address of an object in memory. Line 1 – x is an integer, give it value 10 Line 3 – p gets the address of x * * * Just like java. But you have to think about pointers. * No garbage collection. * * * Ask about virtual. (what’s wrong here…) * * Using p to “point” at the method. * On the left we have a pointer that we must dereference. Still must delete p on the left – problem. on the right, everything is ok. C++ Mini-Course  Part 1: Mechanics Part 2: Basics CPSC 221, Texas AM University Adapted from: Brown CS123 /courses/cs123/resources/c++_mini_course.ppt C++ Mini-Course Part 1: Mechanics C++ is a superset of C New Features include Classes (Object Oriented) Templates (Standard Template Library) Operator Overloading Slightly cleaner memory operations Some C++ code #ifndef __SEGMENT_HEADER__ #define __SEGMENT_HEADER__ class Point; class Segment { public: Segment(); virtual ~Segment(); private: Point *m_p0, *m_p1; }; #endif // __SEGMENT_HEADER__ Segment.h #include “Segment.h” #include “Point.h” Segment::Segment() { m_p0 = new Point(0, 0); m_p1 = new Point(1, 1); } Segment::~Segment() { delete m_p0; delete m_p1; } Segment.cpp #include “Segment.h” #include iostream #include Insert header file at this point. Use library header. Header Guards #ifndef __SEGMENT_HEADER__ #define __SEGMENT_HEADER__ // contents of Segment.h //... #endif To ensure it is safe to include a file more than once. Header Guards #ifndef __SEGMENT_HEADER__ #define __SEGMENT_HEADER__ // contents of segment.H //... #endif To ensure it is safe to include a file more than once. If this variable is not def