Why doesnt this method call work?

Guest User

Hi

I have the following code example:-

class Program
{
static void Sum(params int[] ints)
{
int sum = 0;

for (int i = 0; i < ints.Length; i++)
{
sum += ints[i];
}
}

static void Main()
{
int[] ints = { 1, 2, 3, 4 };

Sum(ints);

Console.WriteLine(ints);
Console.ReadLine();
}

}

I was expecting the calling method "Main" to reflect the changes in the called method "Sum" as the array of ints is passed by reference?

Regards

Steven

2 Replies

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Vulpes14y ago
Accepted answer
Well, the array is actually being passed by value but, as arrays are reference types, any changes to the array's elements will be persisted when the method returns.

However, there aren't any changes to the array's elements - they're just added up - and so the array remains unchanged when the method returns.

However, if you alter the program to this you will see the changes to the array persisted:

class Program
{
static void Sum(params int[] ints)
{
int sum = 0;

for (int i = 0; i < ints.Length; i++)
{
ints[i] *= 2;
sum += ints[i];
}
}

static void Main()
{
int[] ints = { 1, 2, 3, 4 };

Sum(ints);

foreach(int i in ints)
{
Console.WriteLine(i);
}
Console.ReadLine();
}

}
Guest User14y ago
Cheers kindly Vulpes