в 14:21, 25 мая 2010

2010-05-25T14:21:17Z

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2010-05-25T10:30:07Z

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==array of pointers to objects==

<source lang="cpp">#include <iostream>
using namespace std;
class person{
protected:
char name[40];
public:
void setName(){
cout << "Enter name: ";
cin >> name;
}
void printName()
{
cout << "\n Name is: " << name;
}
};
int main()
{
person* persPtr[100];
int n = 0;
char choice;

do{
persPtr[n] = new person;
persPtr[n]->setName();
n++;
cout << "Enter another (y/n)? ";
cin >> choice;
}while( choice=="y" );

for(int j=0; j<n; j++){
cout << "\nPerson number " << j+1;
persPtr[j]->printName();
}
cout << endl;
return 0;
}</source>

==assign the address of a public member of an object to a pointer and then access that member by using the pointer==

<source lang="cpp">#include <iostream>
using namespace std;

class cl {
public:
int i;
cl(int j) { i=j; }
};

int main()
{
cl ob(1);
int *p;

p = &ob.i; // get address of ob.i

cout << *p; // access ob.i via p

return 0;
}</source>

==dereferencing the pointer returned by new==

<source lang="cpp">#include <iostream>
using namespace std;
class Distance
{
private:
int feet;
float inches;
public:
void getdist() {
cout << "\nEnter feet: ";
cin >> feet;
cout << "Enter inches: ";
cin >> inches;
}
void showdist(){
cout << feet << "\"-" << inches << "\"";
}
};
int main(){
Distance& dist = *(new Distance);

dist.getdist();
dist.showdist();
cout << endl;
return 0;
}</source>

==Pointers to Objects==

<source lang="cpp">#include <iostream>
using namespace std;

class cl {
int i;
public:
cl(int j) { i=j; }
int get_i() { return i; }
};

int main()
{
cl ob(88), *p;

p = &ob; // get address of ob

cout << p->get_i(); // use -> to call get_i()

return 0;
}</source>

==uses a pointer to access all three elements of array ob after being assigned ob"s starting address==

<source lang="cpp">#include <iostream>
using namespace std;

class cl {
int i;
public:
cl() { i=0; }
cl(int j) { i=j; }
int get_i() { return i; }
};

int main()
{
cl ob[3] = {1, 2, 3};
cl *p;
int i;

p = ob; // get start of array
for(i=0; i<3; i++) {
cout << p->get_i() << "\n";
p++; // point to next object
}

return 0;
}</source>

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