Csharp Interview Questions :: Variables Scope and Lifetime :: Basic

• Variables Scope and Lifetime - Basic

Correct output for the following set of code is :

class Program
{
public static void Main(string[] args)
{
int i, j;
i = (j = 10) + 20;
Console. WriteLine(i);
Console. WriteLine(j);
Console. ReadLine();
}
}

Answer:

Explanation:

Select the output for the following set of code:

public static void Main(string[] args)
{
int i = 200;
object o = i;
int n =(int) o;
o = 100;
System. Console. WriteLine("The value-type value = {0}", n);
System. Console. WriteLine("The object-type value = {0}", o);
Console. ReadLine();
}

Answer:

Explanation:

The concept of ‘unboxing’ is implemented here . To ‘unbox’ an object back to value type, we have to do it explicitly as “int n = (int) o”. So the output: 200, 100

Select the output for the following set of code:

public static void Main(string[] args)
{
int i = 256;
object o = i;
i = 500;
System. Console. WriteLine("The value-type value = {0}", i);
System. Console. WriteLine("The object-type value = {0}", o);
Console. ReadLine();
}

Answer:

Explanation:

The concept of boxing is implemented here. The variable 'i' is value type and object is reference type. So even if we initialize the value of 'i' again, the object value remains the same. So the output will be 500, 256

• Variables Scope and Lifetime - Basic