... [(20,40)(40,60) Hello] Chương trình 1Rectangle: [(0,0)(50,100)]Square: [(0,0)(50,50)]Textbox: [(0,0)(10,10) Hello] Chương trình 24© 2004, HOÀNG MINH SƠN Chương 7: Quan hệ lớp©2007 AC - HUTBiểu ₫ồ ... y; X* px = &y; //Typ-Convert Y* to X*px->f1(); //virtual function Y::f1()px->f2(); //virtual function X::f2()px->f3(); //virtual function X::f3()px->f4(); //function X::f4() ... lớp (Unified Modeling Language)Quan hệ dẫnxuấtQuan hệ chứa© 2004, HOÀNG MINH SƠN Chương 1 Kỹ thuật lập trình 010101010101010110000101010101010101011000010101010101010101100001010101010010101010010101010101001010101001010101010100101010100101101001100011001001001010100110001100100100101010011000110010010010110010110010001000001011001011001000100000101100101100100010000010010101010101010110000101010101010101011000010101010101010101100001010101010010101010010101010101001010101001010101010100101010100101101001100011001001001010100110001100100100101010011000110010010010110010110010001000001011001011001000100000101100101100100010000010010101010101010110000101010101010101011000010101010101010101100001010101010010101010010101010101001010101001010101010100101010100101101001100011001001001010100110001100100100101010011000110010010010110010110010001000001011001011001000100000101100101100100010000010y...