C# 4 and .NET 4

Jagged arrays ❘ 133
You can also initialize the two - dimensional array by using an array indexer if you know the value for the
elements in advance. For the initialization of the array, one outer curly bracket is used, and every row is
initialized by using curly brackets inside the outer curly brackets.
int[,] twodim = {
{1, 2, 3},
{4, 5, 6},
{7, 8, 9}
};
When using an array initializer, you must initialize every element of the array. It is not
possible to leave the initialization of some values for later.
By using two commas inside the brackets, you can declare a three - dimensional array:
int[,,] threedim = {
{ { 1, 2 }, { 3, 4 } },
{ { 5, 6 }, { 7, 8 } },
{ { 9, 10 }, { 11, 12 } }
};
Console.WriteLine(threedim[0, 1, 1]);
jagged arrays
A two - dimensional array has a rectangular size (for example, 3 3 elements). A jagged array is more
fl ex ibl e i n si z i n g t h e a r r ay. W it h a ja g g e d a r r ay e ve r y row c a n h ave a d i f f e re nt si z e .
Figure 6 - 4 contrasts a two - dimensional array that has 3 3 elements with a jagged array. The jagged array
shown contains three rows where the fi rst row has two elements, the second row has six elements, and the
third row has three elements.
Two-Dimensional Array
Jagged Array
1 2 3
1 2
4 5 6
7 8 9
3 4 5 6 7 8
9 10 11
figure 6-4
A jagged array is declared by placing one pair of opening and closing brackets after another. With the
initialization of the jagged array, only the size that defi nes the number of rows in the fi rst pair of brackets
is set. The second brackets that defi ne the number of elements inside the row are kept empty because every
row has a different number of elements. Next, the element number of the rows can be set for every row:
int[][] jagged = new int[3][];
jagged[0] = new int[2] { 1, 2 };
jagged[1] = new int[6] { 3, 4, 5, 6, 7, 8 };
jagged[2] = new int[3] { 9, 10, 11 };
code snippet Sample1/Program.cs
Iterating through all elements of a jagged array can be done with nested for loops. In the outer for loop
every row is iterated, and the inner for loop iterates through every element inside a row.
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