.net - C#: Variable changes value while processing -

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• what kind of memory semantics govern array assignment in c#? 7 answers

my variable changes value while processing. here's code.

private string[] rawlayer; private string[] lastrawlayer;  public bool getdisplaymessage(string message) {     lastrawlayer = rawlayer;      rawlayer[0] = "1";      console.writeline(lastrawlayer[0]); //output = "1"      return true; } 

why output "1"?

when calling lastrawlayer = rawlayer; add new reference array rawlayer instead of creating new array. every change done rawlayer reflected within lastrawlayer , vice versa. if want make deep copy of array have re-create it:

lastrawlayer = rawlayer.toarray(); 

alternativly use array.copyto:

rawlayer.copyto(lastrawlayer, 0); 

which copy every element of rawlayer second array. if have custom objects stored within array have re-create objects if want avoid change of instance @ index 0 example reflected in both arrays. following still true:

person[] arr1 = new [] { new person { name = "tim" } } person[] arr2 = new person[arr.length]; arr1.copyto(arr2); arr1[0].name = "hans";    // changes value references "tim" console.writeline(arr2[0].name); 

the code above print "hans" instead of "tim" because although have different arrays arrays reference same instances of person.