C# Questions & Answers ? Pointers Operation ? 1
Posted by Superadmin on August 23 2022 14:04:36

C# Questions & Answers – Pointers Operation – 1

This section of our 1000+ C# MCQs focuses on operation on pointers in C# Programming Language.

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

```
 class UnsafeCode
```
```
 {
```
```
     unsafe static void Main()
```
```
     {
```
```
         int m = 10;
```
```
         int *mptr = &m;
```
```
         int **ptr = &mptr;
```
```
         int n = 20;
```
```
         int *nptr = &n;
```
```
         int **prt = &nptr;
```
```
         m = **prt + *nptr;
```
```
         n = *mptr* **prt;
```

         Console.WriteLine(n + " " + m);

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

a) 20 200
b) 40 200
c) 800 40
d) 40 800

Answer: c
Explanation: None.
Output: 800 40

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

```
 unsafe static void Main()
```
```
 {
```
```
     int a = 5;
```
```
     int b = 5;
```
```
     int c = 5;
```
```
     int*[] ptr = new int* [3];
```
```
     ptr[0] = &a;
```
```
     ptr[1] = &b;
```
```
     ptr[2] = &c;
```
```
     for (a = 0; a < 3; a++)
```
```
     {
```
```
         c += *ptr[a];
```
```
         Console.WriteLine(c);
```
```
     }
```
```
     Console.ReadLine();
```
```
 }
```

a) 5 10
b) 10 20
c) Compile time error
d) 5 10 20

Answer: d
Explanation: None.
Output:5 10 20

3. 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)
```
```
        {
```
```
            ptrs[i] = ptrs[i]* 3;
```
```
            ptrs[i] = ptrs[i] + 4;
```
```
            Console.WriteLine(ptrs[i]);
```
```
        }
```
```
        Console.ReadLine();
```
```
    }
```
```
}
```

a) 20, 10, 7
b) 13, 10, 7
c) 6, 9, 3
d) Compile time error

Answer: b
Explanation: None.
Output: 13, 10, 7

4. Among the given pointers which of the following cannot be incremented?
a) int
b) char
c) float
d) void

Answer: d
Explanation: None.

5. A structure pointer points to __________
a) first member of structure
b) first two members of structure
c) whole structure
d) only to the last member of structure

Answer: c
Explanation: None.

6. What will be the declaration of the variable ptr as the pointer to array of 6 floats?
a) float *ptr[6]
b) float [6]*ptr
c) float(*ptr)[6]
d) float(*ptr)(6).

Answer: c
Explanation: None.

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

```
 class UnsafeCode
```
```
 {
```
```
     unsafe static void Main()
```
```
     {
```

         char[] arr = { 'A', 'B', 'C', 'D', 'E' };

```
         fixed (char* P = arr)
```
```
         {
```
```
             int i;
```
```
             for (i = 0 ;i < 5 ;i++)
```
```
             if (*P % 2 == 0)
```
```
             ++*P;
```
```
             else
```
```
             (*P)++;
```
```
             Console.WriteLine(arr);
```
```
         }
```
```
         Console.ReadLine();
```
```
     }
```
```
 }
```

a) ACCEE
b) FBCDE
c) BBDDF
d) BBCEE

Answer: b
Explanation: None.
Output:FBCDE

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

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

         Console.WriteLine("Index pointer like array.");

```
         fixed (int* p = nums)
```
```
         {
```

             for (int i = 0 ;i <10 ;i++)

```
             p[i] = i;
```

             for (int i = 10 ;i >0 ;i--)

             Console.WriteLine("p[{0}]: {1} ", i, p[i]);

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

a) p[10] :0, p[9] :9, p[8] :8…..p[1]:1
b) p[10] : 1, p[9] :2, p[8] :3…..p[1] :0
c) p[1] : 1, p[2] :2, p[3] :3…..p[10] :0
d) Compile time error

Answer: a
Explanation: None.
Output:Index pointer like array:
p[10] :0, p[9] :9, p[8] :8…p[1]:1

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

```
 class UnsafeCode
```
```
 {
```
```
     unsafe static void Main()
```
```
     {
```
```
         string str = "this is a test";
```
```
 
```
```
             fixed (char* p = str)
```
```
            {
```

                for (int i = str.Length-1 ;p[i] != 0 ;i--)

```
                Console.Write(p[i]);
```
```
            }
```
```
        Console.ReadLine();
```
```
    }
```
```
 }
```

a) test a is this
b) compile time error
c) tset a si siht
d) run time error

Answer: c
Explanation: Reversal of string using pointers.
Output:tset a si siht

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

```
 class UnsafeCode
```
```
 {
```
```
     unsafe static void Main()
```
```
     {
```
```
         int* p ;
```
```
         int ch = 13*5;
```
```
         p = &(ch);
```

         Console.WriteLine(Convert.ToChar(*p));

```
         if (*p == 'A')
```

         Console.WriteLine(Convert.ToBoolean(1));

```
         else
```

         Console.WriteLine(Convert.ToBoolean(0));

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

a) 65 False
b) 65 1
c) A True
d) A 1

Answer: c
Explanation: Convert.Tochar(*p) = A
Convert.ToBoolean(1) = True
Output: A
True