Re: How does "new" work in a loop?


Tony Sinclair wrote:
I'm just learning C#. I'm writing a program (using Visual C# 2005 on
WinXP) to combine several files into one (HKSplit is a popular
freeware program that does this, but it requires all input and output
to be within one directory, and I want to be able to combine files
from different directories into another directory of my choice).

My program seems to work fine, but I'm wondering about this loop:


for (int i = 0; i < numFiles; i++)
{
// read next input file

FileStream fs = new FileStream(fileNames[i],
FileMode.Open, FileAccess.Read, FileShare.Read);
Byte[] inputBuffer = new Byte[fs.Length];

fs.Read(inputBuffer, 0, (int)fs.Length);
fs.Close();

//append to output stream previously opened as fsOut

fsOut.Write(inputBuffer, 0, (int) inputBuffer.Length);
progBar.Value++;
} // for int i

As you can see, the objects fs and inputBuffer are both created as
"new" each time through the loop, which could be many times. I didn't
think this would work; I just tried it to see what kind of error
message I would get, and I was surprised when it ran. Every test run
has produced perfect results.

So what is happening here? Is the memory being reused, or am I piling
up objects on the heap that will only go away when my program ends, or
am I creating a huge memory leak?

Unlikely that you are creating a memory leak. C# uses garbage
collection.
When the object goes out of scope (in your case, the } marked // for
int i)
the object is destroyed. The next time through the loop, a new one is
created.

Matt

.

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