C# Tutorial – 07 – Arrays
An array is a data structure used for storing a collection of values that all have the same date type.
Array declaration
To declare an array, a set of square brackets is appended to the data type the array will contain, followed by the array’s name. An array can be declared with any data type and all of its elements will then be of that type.
int[] x; // not int x[]
Array allocation
The array is allocated with the new keyword, followed again by the data type and a set of square brackets containing the length of the array. This is the fixed number of elements that the array can contain. Once the array is created, the elements will automatically be assigned to the default value for that data type.
int[] x = new int[3];
Array assignment
To fill the array elements they can be referenced one at a time and then assigned values. An array element is referenced by placing the element’s index inside square brackets. Notice that the index for the first element starts with zero.
x[0] = 1; x[1] = 2; x[2] = 3;
Alternatively, the values can be assigned all at once by using a curly bracket notation. The new keyword and data type may optionally be left out if the array is declared at the same time.
int[] y = new int[] { 1, 2, 3 }; int[] z = { 1, 2, 3 };
Array access
Once the array elements are initialized, they can be accessed by referencing the elements’ indexes inside the square brackets.
System.Console.Write(x[0] + x[1] + x[2]); // 6
Rectangular arrays
There are two kinds of multi-dimensional arrays in C#: rectangular and jagged. A rectangular array has the same length of all sub-arrays and separates the dimensions using a comma.
string[,] x = new string[2, 2];
As with single-dimensional arrays, they can either be filled in one at a time or all at once during the allocation.
x[0, 0] = "00"; x[0, 1] = "01"; x[1, 0] = "10"; x[1, 1] = "11"; string[,] y = { { "00", "01" }, { "10", "11" } };
Jagged arrays
Jagged arrays are arrays of arrays, and can have irregular dimensions. The dimensions are allocated one at a time and the sub-arrays can therefore be allocated to different sizes.
string[][] a = new string[2][]; a[0] = new string[1]; a[0][0] = "00"; a[1] = new string[2]; a[1][0] = "10"; a[1][1] = "11";
It is possible to assign the values during the allocation.
string[][] b = { new string[] { "00", "01" }, new string[] { "10", "11" } };
These are all examples of two-dimensional arrays. If more than two dimensions are needed, more commas can be added for the rectangular array, or more square brackets for the jagged array.
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i used rectangular method to declare nd use jagged type array nd that works …. so in that case why they are mentioned differently ??
A rectangular array will always have the same length for all elements. If you want different lengths for the elements the jagged array is needed.
@mikzi
you wrote Console.Write(x[0] + x[1] + x[2]);
it will print the sum of all data in ‘x’ instead of printing the actual value … which we were looking for (to access)
s/l fr tht Console.WriteLine(a[0] +”"+ a[1] +”"+ a[2] +”"+ b [0] +”"+ b[1] +”"+ b[2] );
That was intentional, but yes if we wanted to print the numbers as strings that is correct.
Error
string a = “An array is a data structure used for storing a collection of values that all have the same date type.”; // Line 1
a = a.Replace(“date type”, “data type”);
Console.WriteLine(a);
:-) :-) :-)
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Keep it up!!!
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It’s almost perfect,: short and easy to understand.
I think, those tutorials will be optimal for beginners.
Thanks.
Yes, this is a programming syntax tutorial. For practical applications of the code you can for example look through some project code at Sourceforge.
Here are only theoeotical concepts are given ..What about practical matteer