C++ Arrays

Inizialization


// Inizialization samples:
int foo [5];

int foo [5] = { 16, 2, 77, 40, 12071 }; 

int bar [5] = { 10, 20, 30 };

int bar [5] = { };

// They are equivalent
int foo[] = { 10, 20, 30 };
int foo[] { 10, 20, 30 };

Store – Access


// Store
foo [2] = 75;

// Access
x = foo[2];

Operations


foo[0] = a;
foo[a] = 75;
b = foo [a+2];
foo[foo[a]] = foo[2] + 5;

Multidimensional Arrays

Multidimensional arrays can be described as “arrays of arrays”. 


int jimmy [3][5];   // is equivalent to
int jimmy [15];     // (3 * 5 = 15)

Arrays as parameters

At some point, we may need to pass an array to a function as a parameter. 


// arrays as parameters
#include <iostream>
using namespace std;

void printarray (int arg[], int length) {
  for (int n=0; n<length; ++n)
    cout << arg[n] << ' ';
  cout << '\n';
}

int main ()
{
  int firstarray[] = {5, 10, 15};
  int secondarray[] = {2, 4, 6, 8, 10};
  printarray (firstarray,3);
  printarray (secondarray,5);
}

The result is:
5 10 15
2 4 6 8 10

Library Array

C++ provides an alternative array type as a standard container. 


#include <iostream>
#include <array>
using namespace std;

int main()
{
  array<int,3> myarray {10,20,30};

  for (int i=0; i<myarray.size(); ++i)
    ++myarray[i];

  for (int elem : myarray)
    cout << elem << '\n';
}

Reference: http://www.cplusplus.com/doc/tutorial/arrays/