Mega Code Archive
0054 Passing Arrays Using ref and out
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An out parameter of an array type must be assigned by the callee.
For example:
static void TestMethod1(out int[] arr)
{
arr = new int[10]; // definite assignment of arr
}
A ref parameter of an array type must be assigned by the caller.
A ref parameter of an array type may be altered as a result of the call.
static void TestMethod2(ref int[] arr)
{
arr = new int[10]; // arr initialized to a different array
}
In this example we use out modifier for array parameter:
class TestOut
{
static void FillArray(out int[] arr)
{
// Initialize the array:
arr = new int[5] { 1, 2, 3, 4, 5 };
}
static void Main()
{
int[] theArray; // Initialization is not required
// Pass the array to the callee using out:
FillArray(out theArray);
// Display the array elements:
foreach (int i in theArray)
{
System.Console.WriteLine(i);
}
}
}
The output:
1
2
3
4
5
The following code shows how to use ref modifier for array parameter.
class MainClass
{
static void FillArray(ref int[] arr)
{
arr[0] = 1111;
arr[4] = 5555;
}
static void Main()
{
// Initialize the array:
int[] theArray = { 1, 2, 3, 4, 5 };
// Pass the array using ref:
FillArray(ref theArray);
// Display the updated array:
foreach (int i in theArray)
{
System.Console.WriteLine(i);
}
}
}
The output:
1111
2
3
4
5555
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