After struggling with an example in the book, I looked in the MSDN and searched these forums.
I believe my book is wrong when it shows:
int[,] student = new in[4][3];
I tried doing it that way but it errors.
int[,] student = new int[5,4];
gives me no error and works.
I am going to go with that.
Unless someone can tell me that int[,] student = new in[4][3]; is indeed a correct format or what kind of a typing error it could be...
The following also seems to be in the wrong format:
int[][] x = { { 2, 3 }, { 4, 5 }, { 6, 7 } };
I don't think you can do it that way...
Multidimensional Arrays
Mix from Latvia
You are more than welcome any time!
Best Regards,
Ryan Stemen
pmanisekaran
int[][] x = { { 2, 3 }, { 4, 5 }, { 6, 7 } };
I tried this inside of main, I tried this as a class property. Still errors.
What would x[ 1 ] be Should it result in just 4, or will it somehow contain 4,5
MarkSee
Yes it is, and this type of array is called Jagged array, Jagged array is a multidimentional array which has variable number of collumn ins each row as in your example first row contains 3 values and second rown contains 4 values!
Best Regards,
Rizwan
Amit Vasu
Ok , I am going to look at that right now...
EDIT:
OMG, you are brilliant. I don't know how you managed to understand what I wanted to see, but you nailed it right on the coffin.
Thank you so much for this. I will look it over some more to understand it and pass along more questions.
Thanks again!
Michaelo1
Ahhhhh, Foolios! I beg your pardon I was wrong.
Listen again:
int[ , ] arr1 = new int[ , ] { {1, 2, 3}, {4, 5, 6}, {7, 8, 9} }; // Its Correct
is a multidimentional array. [ , ] is used for Multidemntioanl arrays in which all rows have same number of elements in the above example all rows have 3 elements.
If you change the above code to:
int[ , ] arr2 = new int[ , ] { {1, 2, 3}, {4, 5, 6}, {7, 8, 9, 10} }; // Its Wrong
Because all should have the same number of elements so this is error!
on the other hand, if you use:
int[][] arr1 = { new int[] { 1, 2, 3 }, new int[] { 4, 5, 6 }, new int[] { 7, 8, 9 } }; // Its Correct
You have to tell what to place on each row
int[][] arr1 = { new int[] { 1, 2, 3 }, new int[] { 4, 5, 6 }, new int[] { 7, 8, 9 , 4, 6, 7, 4, 4} }; // Its Correct and can contain different number of elements tan other rows
int[][] x = { { 2, 3 }, { 4, 5 }, { 6, 7 } }; // Is in correct You have to use new int[] before each set of number in {}
I hope this will help!
Best Regards,
nguyentanbao
From the above explaination It seems you have understood completely!
foreach loop is a safe way to iterate through a collection without getting out of range from the array (avoiding Exception). It'll iterate automatically to the numbers which are in array not 1 above or less!
Anything else needed Welcome!
Best Regards,
Rizwan
DavidR100
I prepared answer of your last post but i think you have deleted that now. Any how I would liek to copy /paste in case you need to understand!
class ParamArrayWithReturn
{
public static void Main()
{
int[][] returned = F(3, 2, 15);
foreach (int[] ints in returned)
{
foreach (int i in ints)
{
Console.Write(i.ToString() + ",");
}
Console.WriteLine();
}
}
public static int[][] F(int n, int m, int value)
{
int[][] x = new int[3][];
for (int i = 0; i < n; i++)
{
x[ i ] = new int[ m ];
for (int j = 0; j < m; j++)
x[ i ][ j ] = value;
}
return x;
}
"Now why would we return x here And what happens to it when it returns to the method call I am confused by that part of the example."
you used function definition something like this:
public static int[][] F(int n, int m, int value)
int[][] after static and before function name, means that this function must return an int[][]. You create fucnctions to get some done work from it and most of the time it should give back the result so here int[] [] is the result of the function which may be needed by its calls. In this example Main function is its caller and see the modified main function I got the F's returned resutl back in int [][] returned in the main. So i can use it for some purpose in main.
if you omit the return x at the end of the function F, project will not compile and compiler will give you error "Not all Code paths return value" it means when you have declared in function definitation that i'll return the value then you must have to return the same things which was written in function definitaiotn int[][] in this case...
Sometimes we create functions and we dont want to get any result back from them and we just want that function should do some processing in itself and should not return any value so we can write function Definitation like this:
public static void F(int n, int m, int value)
I have replaced int[][] with void that means this fucnion will not return any thing. Generally Speaking void means emptu or nothing. Now even if you dont write return x, your code wil be compiled just fine. So it depends on your needs, that some times you want some resutl back from function and some times not.
In you call you the function F you didnot assing the result back from the function to any int[][]; I modified it to see what result came from the function and then printed it similar to the format in which it is stored in the array!
Remember, a function can return only one value at a time, whether it is an array, any object of class, struct even any reference or value type.
I hope you understand now! if you face any difficult please feel freee to ask 100 times again!
Best Regards,
Rizwan
Pr0fess0rX
int[][] x = { new int[] { 2, 3, 4 }, new int[] { 5, 6, 7, 8, 9 } };
ok so
int[][] x = { { 2, 3, 4 }, { 5, 6, 7, 8, 9 } };
would not be proper shorthand then right
Hila123
int[][] returned = F(3, 2, 15);
foreach (int[] ints in returned)
{
foreach (int i in ints)
I see how you have a foreach set up to completely cycle through all the elements of the jagged array. I see how it says, foreach outer array index we'll use a temp variable named ints to cycle through the array called returned. I see that outer array as int[] in the first foreach loop, the outer foreach if you will. The inner foreach loop then uses an int variable to cycle through each index of the temporary named ints array which is the inner array.See what you guys have all taught me right here on this forum Damned, that's awesome: I honestly thought I had no hope of understanding anything just a couple weeks ago. Thanks so much!
Andre&#39;s
hi,
this is multidimension Array
int [,] x= new int[2,2];
the best thing you can relate this with a fixed size table (2 rows , 2 columns) you can't add more than that to the table
this is jagged Array
int[][] y = new int[2][];
in this array you specify the number of rows but you don't specify the number of columns
the best word to discripe this type of arrays is " Array of Arrayes"
int[][] x = { new int[] { 2, 3, 4 }, new int[] { 5, 6, 7, 8, 9 } };every row may have different dimensions like here first row has 3 columns but second row has 5 columns
hope this helps