Microsoft .NET preguntas y respuestas de entrevista
Pregunta 1. Write code for a case statement.
switch (n)
{
case 1:
x=1;
break;
case 2:
x=2;
break;
default:
goto case 1;
}
Pregunta 2. Is a struct stored on the heap or stack?
Stack
Pregunta 3. Can a struct have methods?
Yes
Pregunta 4. What is checked { } and unchecked { }?
By default C# does not check for overflow (unless using constants), we can use
checked to raise an exception. E.g.:
static short x = 32767; // Max short value
static short y = 32767;
// Using a checked expression
public static int myMethodCh()
{
int z = 0;
try
{
z = checked((short)(x + y));
//z = (short)(x + y);
}
catch (System.OverflowException e)
{
System.Console.WriteLine(e.ToString());
}
return z; // Throws the exception OverflowException
}
This code will raise an exception, if we remove unchecked as in:
//z = checked((short)(x + y));
z = (short)(x + y);
Then the cast will raise no overflow exception and z will be assigned –2. unchecked can
be used in the opposite way, to say avoid compile time errors with constanst overflow.
E.g. the following will cause a compiler error:
const short x = 32767; // Max short value
const short y = 32767;
public static int myMethodUnch()
{
int z = (short)(x + y);
return z; // Returns -2
}
The following will not:
const short x = 32767; // Max short value
const short y = 32767;
public static int myMethodUnch()
{
int z = unchecked((short)(x + y));
return z; // Returns -2
}
Pregunta 5. Can C# have global overflow checking?
Yes
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