Arrays and Loops

Arrays can be conveniently initialized by using a loop. The statement:

for(int i = 0; i < 10; i++)
      arrayOfInt[i] = i;

initializes each of the ten array elements to the corresponding index. For bi-dimensional arrays two nested loops can be used. The following statement initializes each element to the product of row and column index:

for(int i = 0; i < 3; i++)
      for(int j = 0; j < 5; j++)
          BiDimensionalArrayOfInt[i][j] = i * j;

Arrays can have any dimension, although using more than three dimensions is strongly advised against in order to avoid the confusion arising by the impossibility to visualize a space in four or more dimensions. A three dimension-array can be initialized by means of three nested loops.

for(int i = 0; i < 2; i++)
      for(int j = 0; j < 3; j++)
            for(int k = 0; k < 4; k++)
                  TriDimensionalArrayOfInt[i][j][k] = i * j * k;

The number of dimensions is also known as the "level" of the array. Arrays are visited – in order to print out their contents, for example – in a similar way.

Example


#include <iostream>
using namespace std;

int main()
{   
     int arrayOfInt[10];
     int BiDimensionalArrayOfInt[3][5];
     int TriDimensionalArrayOfInt[2][3][4];

     for(int i = 0; i < 10; i++)
           arrayOfInt[i] = i;

     for(int i = 0; i < 3; i++)
           for(int j = 0; j < 5; j++)
                BiDimensionalArrayOfInt[i][j] = i * j;

     for(int i = 0; i < 2; i++)
           for(int j = 0; j < 3; j++)
                for(int k = 0; k < 4; k++)
                     TriDimensionalArrayOfInt[i][j][k] = i * j * k;

     cout << "one-dimension array:\n\n";
     for(int i = 0; i < 10; i++)
           cout << arrayOfInt[i] << endl;

     cout << "\n\n";

     cout << "two-dimension array:\n\n";
     for(int i = 0; i < 3; i++)
     {
           for(int j = 0; j < 5; j++)
           {
                cout << BiDimensionalArrayOfInt[i][j] << " ";
           }
           cout << endl;
     }

     cout << "\n\n";

     cout << "three-dimension array:\n\n";
     for(int i = 0; i < 2; i++)
           for(int j = 0; j < 3; j++)
                for(int k = 0; k < 4; k++)
                     cout << "level " << i << " row " << j << " column " << k << ", content:" << TriDimensionalArrayOfInt[i][j][k] << endl;             
}

Output

one-dimension array:

0
1
2
3
4
5
6
7
8
9


two-dimension array:

0 0 0 0 0
0 1 2 3 4
0 2 4 6 8


three-dimension array:

level 0 row 0 column 0, content:0
level 0 row 0 column 1, content:0
level 0 row 0 column 2, content:0
level 0 row 0 column 3, content:0
level 0 row 1 column 0, content:0
level 0 row 1 column 1, content:0
level 0 row 1 column 2, content:0
level 0 row 1 column 3, content:0
level 0 row 2 column 0, content:0
level 0 row 2 column 1, content:0
level 0 row 2 column 2, content:0
level 0 row 2 column 3, content:0
level 1 row 0 column 0, content:0
level 1 row 0 column 1, content:0
level 1 row 0 column 2, content:0
level 1 row 0 column 3, content:0
level 1 row 1 column 0, content:0
level 1 row 1 column 1, content:1
level 1 row 1 column 2, content:2
level 1 row 1 column 3, content:3
level 1 row 2 column 0, content:0
level 1 row 2 column 1, content:2
level 1 row 2 column 2, content:4
level 1 row 2 column 3, content:6

C++

Arrays and Loops

Example

Output