Download C++ Problems about constructor, arrays and others. and more Lecture notes Programming Languages in PDF only on Docsity!
listing 1 #include using namespace std;
class array { int nums[10]; public: array(); void set(int n[10]); void show(); array operator+(array ob2); array operator-(array ob2); int operator==(array ob2); };
array::array() { int i; for(i=0; i<10; i++) nums[i] = 0; }
void array::set(int *n) { int i;
for(i=0; i<10; i++) nums[i] = n[i]; }
void array::show() { int i;
for(i=0; i<10; i++) cout << nums[i] << ' ';
cout << "\n"; }
// Fill in operator functions.
int main() { array o1, o2, o3;
int i[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
o1.set(i); o2.set(i);
o3 = o1 + o2; o3.show();
o3 = o1 - o3; o3.show();
if(o1==o2) cout << "o1 equals o2\n"; else cout << "o1 does not equal o2\n";
if(o1==o3) cout << "o1 equals o3\n"; else cout << "o1 does not equal o3\n";
return 0; }
listing 2 #include using namespace std;
class base { int x; public: void setx(int n) { x = n; } void showx() { cout << x << '\n'; } };
// Inherit as public. class derived : public base { int y; public: void sety(int n) { y = n; } void showy() { cout << y << '\n'; } };
int main() { derived ob;
ob.setx(10); // access member of base class ob.sety(20); // access member of derived class
ob.showx(); // access member of base class ob.showy(); // access member of derived class
return 0; }
listing 3 class base { int x; public: void setx(int n) { x = n; } void showx() { cout << x << '\n'; } };
// Inherit as public - this has an error! class derived : public base { int y; public:
int x; public: void setx(int n) { x = n; } void showx() { cout << x << '\n'; } };
// Inherit base as private. class derived : private base { int y; public: // setx is accessible from within derived void setxy(int n, int m) { setx(n); y = m; } // showx is accessible from within derived void showxy() { showx(); cout << y << '\n'; } };
int main() { derived ob;
ob.setxy(10, 20);
ob.showxy();
return 0; }
listing 7 #include using namespace std;
class mybase { int a, b; public: int c; void setab(int i, int j) { a = i; b = j; } void getab(int &i, int &j) { i = a; j = b; } };
class derived1 : public mybase { // ... };
class derived2 : private mybase { // ... };
int main() { derived1 o1; derived2 o2; int i, j;
// ...
listing 8 #include using namespace std;
class samp { // private by default int a; protected: // still private relative to samp int b; public: int c;
samp(int n, int m) { a = n; b = m; } int geta() { return a; } int getb() { return b; } };
int main() { samp ob(10, 20);
// ob.b = 99; Error! b is protected and thus private ob.c = 30; // OK, c is public
cout << ob.geta() << ' '; cout << ob.getb() << ' ' << ob.c << '\n';
return 0; }
listing 9 #include using namespace std;
class base { protected: // private to base int a, b; // but still accessible by derived public: void setab(int n, int m) { a = n; b = m; } };
class derived : public base { int c; public: void setc(int n) { c = n; }
// this function has access to a and b from base void showabc() { cout << a << ' ' << b << ' ' << c << '\n'; } };
using namespace std;
class base { public: base() { cout << "Constructing base class\n"; } ~base() { cout << "Destructing base class\n"; } };
class derived : public base { public: derived() { cout << "Constructing derived class\n"; } ~derived() { cout << "Destructing derived class\n"; } };
int main() { derived o;
return 0; }
listing 12 #include using namespace std;
class base { public: base() { cout << "Constructing base class\n"; } ~base() { cout << "Destructing base class\n"; } };
class derived : public base { int j; public: derived(int n) { cout << "Constructing derived class\n"; j = n; } ~derived() { cout << "Destructing derived class\n"; } void showj() { cout << j << '\n'; } };
int main() { derived o(10);
o.showj();
return 0; }
listing 13 #include using namespace std;
class base { int i; public: base(int n) { cout << "Constructing base class\n"; i = n; } ~base() { cout << "Destructing base class\n"; } void showi() { cout << i << '\n'; } };
class derived : public base { int j; public: derived(int n) : base(n) { // pass arg to base class cout << "Constructing derived class\n"; j = n; } ~derived() { cout << "Destructing derived class\n"; } void showj() { cout << j << '\n'; } };
int main() { derived o(10);
o.showi(); o.showj();
return 0; }
listing 14 #include using namespace std;
class base { int i; public: base(int n) { cout << "Constructing base class\n"; i = n; } ~base() { cout << "Destructing base class\n"; } void showi() { cout << i << '\n'; } };
class derived : public base { int j; public: derived(int n, int m) : base(m) { // pass arg to base class cout << "Constructing derived class\n"; j = n;
int getlen() { return len; } void show() { cout << get() << '\n'; } };
int main() { myderived ob("hello");
ob.show(); cout << ob.getlen() << '\n';
return 0; }
listing 17 #include using namespace std;
// A base class for various types of vehicles. class vehicle { int num_wheels; int range; public: vehicle(int w, int r) { num_wheels = w; range = r; } void showv() { cout << "Wheels: " << num_wheels << '\n'; cout << "Range: " << range << '\n'; } };
class car : public vehicle { int passengers; public: // insert car() constructor here void show() { showv(); cout << "Passengers: " << passengers << '\n'; } };
class truck : public vehicle { int loadlimit; public: // insert truck() constructor here void show() { showv(); cout << "loadlimit " << loadlimit << '\n'; }
int main() { car c(5, 4, 500); truck t(30000, 12, 1200);
cout << "Car: \n"; c.show(); cout << "\nTruck:\n"; t.show();
return 0; }
listing 18 car ob(passengers, wheels, range); truck ob(loadlimit, wheels, range);
listing 19 // Multiple Inheritance #include using namespace std;
class B1 { int a; public: B1(int x) { a = x; } int geta() { return a; } };
// Inherit direct base class. class D1 : public B1 { int b; public: D1(int x, int y) : B1(y) // pass y to B { b = x; } int getb() { return b; } };
// Inherit a derived class and an indirect base. class D2 : public D1 { int c; public: D2(int x, int y, int z) : D1(y, z) // pass args to D { c = x; }
/* Because bases inherited as public, D2 has access to public elements of both B1 and D1. */ void show() {
int main() { D ob(1, 2, 3);
ob.show();
return 0; }
listing 21 #include using namespace std;
class B1 { public: B1() { cout << "Constructing B1\n"; } ~B1() { cout << "Destructing B1\n"; } };
class B2 { int b; public: B2() { cout << "Constructing B2\n"; } ~B2() { cout << "Destructing B2\n"; } };
// Inherit two base classes. class D : public B1, public B2 { public: D() { cout << "Constructing D\n"; } ~D() { cout << "Destructing D\n"; } };
int main() { D ob;
return 0; }
listing 22 #include using namespace std;
class A { public: A() { cout << "Constructing A\n"; } ~A() { cout << "Destructing A\n"; } };
class B { public:
B() { cout << "Constructing B\n"; } ~B() { cout << "Destructing B\n"; } };
class C : public A, public B { public: C() { cout << "Constructing C\n"; } ~C() { cout << "Destructing C\n"; } };
int main() { C ob;
return 0; }
listing 23 #include using namespace std;
class A { int i; public: A(int a) { i = a; } };
class B { int j; public: B(int a) { j = a; } };
class C : public A, public B { int k; public: /* Create C() so that it initializes k and passes arguments to both A() and B() */ };
listing 24 // This program uses a virtual base class. #include using namespace std;
class base { public: int i; };
// Inherit base as virtual. class derived1 : virtual public base { public: int j;
circumference = 2r*3.1416.) / / Create a function called show() that displays the information. */ };
int main() { earth ob(93000000, 365);
ob.show();
return 0; }
listing 28 /* A variation on the vehicle hierarchy. But this program contains an error. Fix it. Hint: try compiling it as is and observe the error messages. */ #include using namespace std;
// A base class for various types of vehicles. class vehicle { int num_wheels; int range; public: vehicle(int w, int r) { num_wheels = w; range = r; } void showv() { cout << "Wheels: " << num_wheels << '\n'; cout << "Range: " << range << '\n'; } };
enum motor {gas, electric, diesel};
class motorized : public vehicle { enum motor mtr; public: motorized(enum motor m, int w, int r) : vehicle(w, r) { mtr = m; } void showm() { cout << "Motor: "; switch(mtr) { case gas : cout << "Gas\n"; break; case electric : cout << "Electric\n";
break; case diesel : cout << "Diesel\n"; break; } } };
class road_use : public vehicle { int passengers; public: road_use(int p, int w, int r) : vehicle(w, r) { passengers = p; } void showr() { cout << "Passengers: " << passengers << '\n'; } };
enum steering { power, rack_pinion, manual };
class car : public motorized, public road_use { enum steering strng; public: car(enum steering s, enum motor m, int w, int r, int p) : road_use(p, w, r), motorized(m, w, r), vehicle(w, r) { strng = s; } void show() { showv(); showr(); showm(); cout << "Steering: "; switch(strng) { case power : cout << "Power\n"; break; case rack_pinion : cout << "Rack and Pinion\n"; break; case manual : cout << "Manual\n"; break; } } };
int main() { car c(power, gas, 4, 500, 5);
c.show();
return 0; }
listing 29
int quadrant; public: quad() { x = 0; y = 0; quadrant = 0; } quad(int x, int y) : coord(x, y) { if(x>=0 && y>=0) quadrant = 1; else if(x<0 && y>=0) quadrant = 2; else if(x<0 && y<0) quadrant = 3; else quadrant = 4; } void showq() { cout << "Point in Quadrant: " << quadrant << '\n'; } quad operator=(coord ob2); };
quad quad::operator=(coord ob2) { cout << "Using quad operator=()\n";
x = ob2.x; y = ob2.y; if(x>=0 && y>=0) quadrant = 1; else if(x<0 && y>=0) quadrant = 2; else if(x<0 && y<0) quadrant = 3; else quadrant = 4;
return *this; }
int main() { quad o1(10, 10), o2(15, 3), o3; int x, y;
o3 = o1 + o2; // add two objects - this calls operator+() o3.get_xy(x, y); o3.showq(); cout << "(o1+o2) X: " << x << ", Y: " << y << "\n";
o3 = o1 - o2; // subtract two objects o3.get_xy(x, y); o3.showq(); cout << "(o1-o2) X: " << x << ", Y: " << y << "\n";
o3 = o1; // assign an object o3.get_xy(x, y); o3.showq(); cout << "(o3=o1) X: " << x << ", Y: " << y << "\n";
return 0; }
