Following is the source code of simple queue implementation with the help of Inheritance and Polymorphism i.e. Late Binding.
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In inheritance, a class (derived class) inherits the features i.e. methods and properties from the parent class (base class). Polymorphism occurs when multiple classes are inherited from each other. Here call to a member function (of the class) causes a different function to be executed (from the classes linked via inheritance) depending on the type of object that invokes the function.
queue implementation C++
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 | #include <dos.h> #include <stdlib.h> #include <iostream.h> #include <conio.h> #include <windows.h> #define MAX 5 // MAXIMUM CONTENTS IN QUEUE class task { public: virtual void dotask() {} task() {} int exists; }; class notep : public task { public: notep() { exists = 1; } void dotask() { system("notepad"); } }; class regt : public task { public: regt() { exists = 1; } void dotask() { system("regedit"); } }; class winex : public task { public: winex() { exists = 1; } void dotask() { system("explorer"); } }; class Bep : public task { public: Bep() { exists = 1; } void dotask() { cout << "\a"; } }; class MsBox : public task { private: char* text; char* caption; int style; public: MsBox(char* ext, char* cap, int no) { text = ext; caption = cap; exists = 1; style = no; } void dotask() { MessageBox(0, text, caption, style); } }; class queue { private: task* t[MAX]; int al; int dl; public: int opt, opt1, a; char te[255], capt[40]; queue() { dl = -1; al = -1; } void del() { task* tmp; if (dl == -1) { cout << "Queue is Empty"; sleep(2); } else { t[dl]->exists = 0; for (int j = 0; j <= al; j++) { if ((j + 1) <= al) { tmp = t[j + 1]; t[j] = tmp; } else { t[al]->exists = 0; al--; if (al == -1) dl = -1; else dl = 0; } } } } void menu() { clrscr(); cout << "1) Add Task \n2)Execute Tasks\n3)Exit Program\n"; // int opt; cin >> opt; switch (opt) { case 1: clrscr(); cout << "1) Open Notepad\n"; cout << "2) Open Explorer\n" << "3) Open Registry\n" << "4) Sound a Beep\n" << "5) MessageBox API\n" << "6) Back\n"; cin >> opt1; if (opt1 != 6) add(opt1); break; case 2: if (al != -1 && dl != -1) { for (int k = 0; k <= al; k++) { if (t[k]->exists == 1) t[k]->dotask(); t[k]->exists = 0; } al = dl = -1; } else { cout << "Queue is Empty"; sleep(3); } break; case 3: exit(0); break; } } void add(int item) { if (dl == -1 && al == -1) { dl++; al++; } else { al++; if (al < max) { } else { cout << "Queue is Full\n"; al--; sleep(3); return; } } switch (item) { case 1: t[al] = new notep; break; case 2: t[al] = new winex; break; case 3: t[al] = new regt; break; case 4: t[al] = new Bep; break; case 5: cout << "\n Enter Style Number:"; cin >> a; t[al] = new MsBox("Task Performed.", "Queue Implementation", a); break; default: cout << "Programming Error"; // No Possibility of this executing }; } }; void main() { queue a; while (1) { a.menu(); } } |
