CLR via C # Note: Method for accepting variable reference types

When the method is implemented in the reuse class, the method fulfills its parameters. For invalid parameters, the method should throw an exception type derived from system. argumentexception.

To build a secure and robust class library, the parameters should be copied to methods that can change the reference type.

Code

# Define Badcode
Using System;
Using System. Threading;

Class Program
{
Static   Void Main ( String [] ARGs)
{
Int [] Denominators = { 1 , 2 , 3 };
Threadpool. queueuserworkitem (divide100by, denominators );

thread. sleep ( 50 );
// external variable parameters
denominators [ 2 ] = 0 ;
console. readline ();
}

Private   Static   Void Divide100by ( Object O)
{
# If Badcode
Int [] Denominators = ( Int []) O;
# Else  
Int [] Denominatorsinput = ( Int []) O;
Int [] Denominators = New   Int [Denominatorsinput. Length];
Array. Copy (denominatorsinput, denominators, denominators. Length );
# Endif
For ( Int Index =   0 ; Index < Denominators. length; index ++ )
{
If (Denominators [Index] =   0 )
{
Throw   New Argumentoutofrangeexception ( " Denominators " , String . Format ( " The index {0} is 0. " , Index ));
}
}
Console. writeline ( " Verification passed " );

Thread. Sleep ( 100 );
// Here, denominators [0] is changed to 0 by external

For ( Int Index =   0 ; Index < Denominators. length; index ++ )
{
Console. writeline ( " 100/{0 }={ 1} " , Denominators [Index], 100   / Denominators [Index]);
}
}
}

 

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