CPP Arrays

Working Array Variables in C++.

An array in the RAM:

• Array is a sequential collection of data storage locations.
• An array holds the same type of data and can be
  primitives (int, double, long ...) and any Object type.

  long LongArray[100];

• This is an array, LongArray, holding 100 elements of long integers.
• The square brackets are in three different ways:
  1. When you want to define an array.
  2. When you want to set an object into the array (as shown above).

     LongArray[index]=100;

     where index is an offset into the array with the value of 0 -> N.
  3. When you want to get a object from the array.

     long item = LongArray[index];

     where index is an offset into the array with the value of 0 -> N.

Initializing Arrays

int IntegerArray[5] = { 10, 20, 30, 40, 50 };    // OK
int IntegerArray[] = { 10, 20, 30, 40, 50 };     // OK
int IntegerArray[5] = { 10, 20, 30, 40, 50, 60}; // Compiler error as too many
int IntegerArray[5] = {10, 20};                  // legal but bad

Multidimensional arrays

// Declaring Multidimensional Arrays (8*8 = 64 of long integers)
long Board[8][8];

// Initializing Multidimensional Arrays  
int theArray[5][3] = { 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 };

// Or for clarity:
int theArray[5][3] = {  {1,2,3},
    {4,5,6},
    {7,8,9},
    {10,11,12},
    {13,14,15} };

#include <iostream>
using namespace std;

int main() {
  int SomeArray[2][5] = { {0,1,2,3,4}, {0,2,4,6,8}};
  for (int i = 0; i<2; i++) {
    for (int j=0; j<5; j++) {
      cout << "SomeArray[" << i << "][" << j << "]: ";
      cout << SomeArray[i][j]<< endl;
    }
  }
  return 0;
}

SomeArray[0][0]: 0
SomeArray[0][1]: 1
SomeArray[0][2]: 2
SomeArray[0][3]: 3
SomeArray[0][4]: 4
SomeArray[1][0]: 0
SomeArray[1][1]: 2
SomeArray[1][2]: 4
SomeArray[1][3]: 6
SomeArray[1][4]: 8

You can download this example here (needed tools can be found in the right menu on this page).