C++/Data Structure/Array Object

Arrays of Objects

<source lang="cpp">

1. include <iostream>

using namespace std; class MyClass {

 int i;

public:

 void setInt(int j) { 
    i=j; 
 }
 int getInt() { 
    return i; 
 }

}; int main() {

 MyClass myObject[3];
 int i;
 for(i=0; i<3; i++) 
    myObject[i].setInt(i+1);
 for(i=0; i<3; i++)
    cout << myObject[i].getInt() << "\n";
 return 0;

}

 </source>

A simple bounded 2-d array example.

<source lang="cpp">

1. include <iostream>
2. include <cstdlib>

using namespace std; class MyArray {

 int isize, jsize;
 int *p;

public:

 MyArray(int i, int j);
 int &put(int i, int j);
 int get(int i, int j);

}; MyArray::MyArray(int i, int j) {

 p = new int [i*j];
 if(!p) {
   cout << "Allocation error\n";
   exit(1);
 }
 isize = i;
 jsize = j;

} int &MyArray::put(int i, int j) {

 if(i <0 || i>=isize || j<0 || j>=jsize) {
   cout << "Bounds error!!!\n";
   exit(1);
 }
 return p[i*jsize + j];

} int MyArray::get(int i, int j) {

 if(i <0 || i>=isize || j<0 || j>=jsize) {
   cout << "Bounds error!!!\n";
   exit(1);
 }
 return p[i*jsize +j]; 

}

int main() {

 MyArray a(2, 3);
 int i, j;
 for(i = 0; i <2; i++)
   for(j=0; j<3; j++)
     a.put(i, j) = i+j;
 for(i = 0; i <2; i++)
   for(j=0; j<3; j++)
     cout << a.get(i, j) << " ";
 a.put(10, 10);
 return 0;

}

 </source>

Define and init class array: two int type parameters in constructor

<source lang="cpp">

1. include <iostream>

using namespace std; class squares {

 int num, sqr;

public:

 squares(int a, int b) { 
    num = a; 
    sqr = b; 
 }
 void show() {
    cout << num << " " << sqr << endl; 
 }

}; int main() {

 squares ob[10] = {
   squares(1, 1),
   squares(2, 4),
   squares(3, 9),
   squares(4, 16),
   squares(5, 25),
   squares(6, 36),
   squares(7, 49),
   squares(8, 64),
   squares(9, 81),
   squares(10, 100)
 };
 int i;
 for(i = 0; i <10; i++) 
    ob[ i ].show();
 return 0;

}

 </source>

Incrementing an object pointer

<source lang="cpp">

1. include <iostream>

using namespace std; class MyClass {

 int num;  

public:

 void set_num(int val) {num = val;}  
 void show_num();  

};

void MyClass::show_num() {

 cout << num << "\n";  

}

main(void) {

 MyClass ob[2], *p;  
    
 ob[0].set_num(10);
 ob[1].set_num(20);  
    
 p = &ob[0];  
 p->show_num(); 
    
 p++;  
 p->show_num(); 
    
 p++; 
 p->show_num(); 
    
 return 0;  

}

 </source>

Init class array: char type

<source lang="cpp">

1. include <iostream>

using namespace std; class CharClass {

 char ch;

public:

 CharClass(char c) { 
    ch = c; 
 }
 char get_ch() { 
    return ch; 
 }

}; int main() {

 CharClass ob[10] = { "a", "b", "c","d", "e", "f", 
                    "g", "h", "i", "j" };
 int i;
 for(i = 0; i <10; i++) 
   cout << ob[ i ].get_ch() << " ";
 cout << endl;
 return 0;

}

 </source>

Init class array: int constructor parameter

<source lang="cpp">

1. include <iostream>

using namespace std; class samp {

 int x;

public:

 samp(int n) { 
    x = n; 
 }
 int getx() { 
    return x; 
 }

}; int main() {

 samp A[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
 int i;
 for(i = 0; i <10; i++) 
    cout << A[ i ].getx() << " ";
 cout << endl;
 return 0;

}

 </source>

Initialize each object in an array by specifying an initialization list

<source lang="cpp">

1. include <iostream>

using namespace std; class MyClass {

 int i;

public:

 MyClass(int j) { 
    i = j; 
 } // constructor
 int getInt() { 
    return i; 
 }

}; int main() {

 MyClass myObject[3] = {1, 2, 3}; // initializers
 int i;
 for(i=0; i<3; i++)
   cout << myObject[i].getInt() << "\n";
 return 0;

}

 </source>

Two dimension object array: reference by index

<source lang="cpp">

1. include <iostream>

using namespace std; class MyClass {

 double a, b;

public:

 MyClass(double x, double y) {
   a = x;
   b = y;
 }
 void show() { 
   cout << a << " " << b << "\n"; 
 }

}; int main() {

 MyClass ob[2][5] = {
   MyClass(1, 1), MyClass(2, 2),
   MyClass(3, 3), MyClass(4, 4),
   MyClass(5, 5), MyClass(6, 6),
   MyClass(7, 7), MyClass(8, 8),
   MyClass(9, 9), MyClass(10, 10)
 };
 int i, j;
 for(i = 0; i <2; i++)
   for(j=0; j<5; j++)
     ob[ i ][j].show();
 cout << "\n";
 return 0;

}

 </source>

Two dimension object array: reference by pointer

<source lang="cpp">

1. include <iostream>

using namespace std; class MyClass {

 double a, b;

public:

 MyClass(double x, double y) {
   a = x;
   b = y;
 }
 void show() { cout << a << " " << b << "\n"; }

}; int main() {

 MyClass ob[2][5] = {
   MyClass(1, 1), MyClass(2, 2),
   MyClass(3, 3), MyClass(4, 4),
   MyClass(5, 5), MyClass(6, 6),
   MyClass(7, 7), MyClass(8, 8),
   MyClass(9, 9), MyClass(10, 10)
 };
 MyClass *p;
 p = (MyClass *) ob;
 int i, j;
 for(i = 0; i <2; i++)
   for(j=0; j<5; j++) {
     p->show();
     p++;
   }
 cout << "\n";
 return 0;

}

 </source>