Users Online

· Guests Online: 38

· Members Online: 0

· Total Members: 188
· Newest Member: meenachowdary055

Forum Threads

Newest Threads

No Threads created

Hottest Threads

No Threads created

Latest Articles

· Do while loop
· The for loop in C
· C while loop
· Pointers in C
· Functions in C

Oh no! Where's the JavaScript?
Your Web browser does not have JavaScript enabled or does not support JavaScript. Please enable JavaScript on your Web browser to properly view this Web site,
or upgrade to a Web browser that does support JavaScript; Firefox, Safari, Opera, Chrome or a version of Internet Explorer newer then version 6.

Articles Hierarchy

Articles Home » C# » C# Question & Answers ? Pointers Operation ? 2

C# Question & Answers ? Pointers Operation ? 2

C# Question & Answers – Pointers Operation – 2

This set of C# Questions and Answers for Freshers focuses on “Pointers Operation – 2”.

1. What will be the output of the following C# code snippet?

```
class UnsafeCode
```
```
{
```
```
    struct MyStruct
```
```
    {
```
```
        public int a;
```
```
        public int b;
```
```
        public int Sum() 
```
```
       { 
```
```
           return a * b; 
```
```
       }
```
```
   }
```
```
   unsafe static void Main()
```
```
   {
```
```
       MyStruct o = new MyStruct();
```
```
       MyStruct* p; 
```
```
       p = &o;
```
```
       p->a = 10; 
```
```
       p->b = 20; 
```

       Console.WriteLine("Value is " + p->Sum());

```
       Console.ReadLine();
```
```
   }
```
```
}
```

a) Compile time error
b) Run time error
c) 200
d) 30

Answer: c
Explanation: A pointer can point to an object of a structure type as long as the structure does not contain reference types. When we access a member of a structure through a pointer, we must use the arrow operator, which is –>, rather than the dot (.) operator.
Output : 200

2. What will be the output of the following C# code snippet?

```
class UnsafeCode
```
```
{
```
```
    struct MyStruct
```
```
    {
```
```
        public int a;
```
```
        public int b;
```
```
        public int Sum() 
```
```
       { 
```
```
           return a / b; 
```
```
       }
```
```
   }
```
```
   unsafe static void Main()
```
```
   {
```
```
       MyStruct o = new MyStruct();
```
```
       MyStruct* p; 
```
```
       p = &o;
```
```
       p->a = 60; 
```
```
       p->b = 15; 
```
```
       int c = 30;
```

       Console.WriteLine("Value is : " + p->Sum()*c);

```
       Console.ReadLine();
```
```
   }
```
```
}
```

a) Compile time error
b) 120
c) Run time error
d) 4

Answer: b
Explanation: None.
Output :

3. What will be the output of the following C# code snippet?

```
class UnsafeCode
```
```
{
```
```
    unsafe static void Main()
```
```
    {
```
```
        int[] nums = new int[10];
```

        fixed (int* p = &nums[0], p2 = nums)

```
        {
```
```
            if (p == p2)
```

            Console.WriteLine("p and p2 point to same address.");

```
            Console.ReadLine();
```
```
        }
```
```
    }
```
```
}
```

a) Run time error
b) Compile time error
c) p and p2 point to the same address
d) Only p2

Answer: c
Explanation: None.
Output:

p and p2 point to same address

4. What will be the output of the following C# code snippet?

```
class UnsafeCode
```
```
{
```
```
    static void Main()
```
```
    {
```
```
        int? count = null;
```
```
        int? result = null;
```
```
        int incr = 10;
```
```
        result = count + incr;
```
```
        if (result.HasValue)
```

            Console.WriteLine("result has this value: " + result.Value);

```
        else
```

            Console.WriteLine("result has no value");

```
        Console.ReadLine();
```
```
    }
```
```
}
```

a) Run time error
b) 0
c) Result has no value
d) Compile time error

Answer: c
Explanation: A nullable object can be used in expressions that are valid for its underlying type. When non-nullable and nullable types are mixed in an operation, the outcome is a nullable value.
Output:

result has no value

5. What will be the output of the following C# code snippet?

```
class UnsafeCode
```
```
{
```
```
    static void Main()
```
```
    {
```
```
        int count = 100;
```
```
        int? result = null;
```
```
        int incr = 10;
```
```
        result = count + incr;
```
```
        if (result.HasValue)
```

            Console.WriteLine("result has this value: " + result.Value);

```
        else
```

            Console.WriteLine("result has no value");

```
        Console.ReadLine();
```
```
    }
```
```
}
```

a) Run time error
b) 110
c) Result has no value
d) Compile time error

Answer: b
Explanation: None.
Output: result has this value :

6. Choose the statement which defines the Nullable type Correctly:
a) A special version of a value type that is represented by a structure
b) A nullable type can also store the value null
c) Nullable types are objects of System.Nullable, where T must be a non nullable value type
d) All of the mentioned

Answer: d
Explanation: A nullable type is a special version of the value type that is represented by a structure. In addition to the values defined by the underlying type, a nullable type can also store the value null. Thus, a nullable type has the same range and characteristics as its underlying type. It simply adds the ability to represent a value which indicates that a variable of that type is unassigned. Nullable types are objects of System.Nullable<T>, where T must be a nonnullable value type.

7. What does the following code depicts?

   i. System.Nullable count;
   ii. bool? done;

a) Code i declares the objects of nullable of type Nullable<T> defined in the System namespace
b) Code ii declares a nullable type in much shorter and in more commonly used way using ‘?’
c) Both Code i declares the objects of nullable of type Nullable<T> defined in the System namespace & Code ii declares a nullable type in much shorter and in more commonly used way using ‘?’
d) None of the mentioned

Answer: c
Explanation: None.

8. Which operator is commonly used to find the size of the type of C#?
a) size()
b) sizeof(type)
c) both size() & sizeof(type)
d) none of the mentioned

Answer: b
Explanation: None.

9. What will be the output of the following C# code snippet?

```
 unsafe struct FixedBankRecord
```
```
 {
```
```
     public fixed byte Name[80]; 
```
```
     public double Balance;
```
```
     public long ID;
```
```
 }
```
```
 class UnsafeCode
```
```
 {
```
```
     unsafe static void Main()
```
```
     {
```

         Console.WriteLine("Size of FixedBankRecord is " + sizeof(FixedBankRecord));

```
         Console.ReadLine();
```
```
     }
```
```
 }
```

a) Run time error
b) 80
c) 96
d) Compile time error

Answer: c
Explanation: The purpose of a fixed-size buffer is to allow the creation of a struct in which the array of elements that make up the buffer are contained within the struct. By using a fixed-size buffer, we let the entire array to be contained within the struct. The overall size of FixedBankRecord is 96, which is the sum of its members.
Output :

10. What will be the output of the following C# code snippet?

```
class UnsafeCode
```
```
{
```
```
    unsafe static void Main()
```
```
    {
```
```
        int* ptrs = stackalloc int[3];
```
```
        ptrs[0] = 1;
```
```
        ptrs[1] = 2;
```
```
        ptrs[2] = 3;
```
```
        for (int i = 2; i >=0; i--)
```
```
        Console.WriteLine(ptrs[i]);
```
```
        Console.ReadLine();
```
```
    }
```
```
}
```

a) 3 2 1
b) 1 2 3
c) None of the mentioned
d) Run time error

Answer: a
Explanation: Allocates memory from the stack by using stackalloc. Here, ptrs is a pointer that receives the address of the memory that is large enough to hold size of number of objects of type ‘int’. Here, type ‘int’ is a non reference type. Finally, stackalloc can be used only in an unsafe context.
Output :

3 2 1

Users Online

Forum Threads

Latest Articles

Articles Hierarchy

C# Question & Answers ? Pointers Operation ? 2

C# Question & Answers – Pointers Operation – 2

Comments

Post Comment

Ratings