250+ TOP MCQs on Do While Loop Statements and Answers

C# multiple choice questions on do while loop statements in C# Programming Language.

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

  1.  static void Main(string[] args)
  2.  {
  3.      int i = 1, j = 2, k = 3;
  4.      do
  5.      {
  6.          Console.WriteLine((Convert.ToBoolean(Convert.ToInt32(i++)))
  7.          && (Convert.ToBoolean(Convert.ToInt32(++j))));
  8.      }while (i <= 3);
  9.      Console.ReadLine();
  10.  }

a) 0 0 0
b) True True True
c) 1 1 1
d) False False False

Answer: b
Clarification: 1 AND 1 = True. Similarly, non zero number || non zero number = True.
Output:

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

  1. static void Main(string[] args)
  2. {
  3.     float i = 1.0f, j = 0.05f;
  4.     do
  5.     {
  6.         Console.WriteLine(i++ - ++j);
  7.     }while (i < 2.0f && j <= 2.0f);
  8.     Console.ReadLine();
  9. }

a) 0.05
b) -0.05
c) 0.95
d) -0.04999995

Answer: d
Clarification: None.
Output :

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

  1. static void Main(string[] args)
  2. {
  3.     int i = 1, j = 5;
  4.     do
  5.     {
  6.         Console.WriteLine(i = i++ * j);
  7.     }while (i <= 10);
  8.     Console.ReadLine();
  9. }

a) 5 10 15 20 25 30 35 40 45 50
b) 5 25
c) 5 11 16 21 26 31 36 41 46 51
d) 5 30

Answer: b
Clarification: For first step of loop i = 1 .So, i++ * j = 1 * 5 = 5. For second step of loop i = 5, j = 5. So, i++ * j = 25. As, i = 25 hence, 25 >=10 loop condition breaks.
Output:

4. For the incomplete C# program below, which of the C# code fragment will not result in an infinite loop?

  1.  static void Main(string[] args)
  2.  {
  3.      int i = 1234 ,j = 0;
  4.       /*ADD CODE HERE */
  5.      Console.WriteLine(j);
  6.  }

a)

 do
    {
        j = j + (i % 10);
    }while ((i = i / 10)!= 0);

b)

do
    {
        j = j + (i % 10);
    }while ((i / 10)!= 0);

c)

do
    {
        j = j + (i % 10);
    }while ((i % 10)!= 0);

d)

do
    {
        j = j + (i % 10);
    }while ((i/10 == 0)!= 0);

View Answer

 

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

  1.  static void Main(string[] args)
  2.  {
  3.      long  x;
  4.      x = Convert.ToInt32(Console.ReadLine());
  5.      do
  6.      {
  7.          Console.WriteLine(x % 10);
  8.      }while ((x = x / 10) != 0);
  9.      Console.ReadLine();
  10.  }
  11.  enter x = 1234.

a) number of digits present in x
b) prints ‘1’
c) prints reverse of x
d) prints sum of digits of ‘x’

Answer: c
Clarification: Reverse of digits using while loop statements.
Output:

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

  1.  static void Main(string[] args)
  2.  {
  3.      int i, s = 0, a = 1, d;
  4.      i = Convert.ToInt32(Console.ReadLine());
  5.      do
  6.      {
  7.          d = i % (2 * 4);
  8.          s = s + d * a;
  9.      }while ((Convert.ToInt32(i = i / (2 * 4))) != 0
  10.       && (Convert.ToBoolean(Convert.ToInt32((a) = (a * 10)))));
  11.      Console.WriteLine(s);
  12.      Console.ReadLine();
  13.  }
  14. enter i = 342.

a) It finds binary equivalent of i
b) It finds octal equivalent of i
c) It finds sum of digits of i
d) It finds reverse of i

Answer: b
Clarification: None.
Output :

7. What is the correct syntax for do while loop?
a)

   do;
   {
    statement;
   }while (condition);

b)

   do(condition)
   {
     statement;
   }while;

c)

   do
   {
     statement;
   }while (condition)

d)

   do
   {
        statement;
   }while (condition);

View Answer

Answer: d
Clarification: By definition
Output:

do
       {
          statement;
        }while (condition);

 

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

  1. static void Main(string[] args)
  2. {
  3.     int x = 10;
  4.     do
  5.     {
  6.         Console.WriteLine( x++);
  7.     }
  8.     while(Convert.ToBoolean(5) && Convert.ToBoolean(4) && Convert.ToBoolean(3)
  9.     && Convert.ToBoolean(2) && Convert.ToBoolean(1) && Convert.ToBoolean(0));
  10.     Console.ReadLine();
  11. }

a) 13
b) 15
c) 11
d) 10

Answer: d

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

  1. static void Main(string[] args)
  2. {
  3.     int x;
  4.     for (x = 10; x <= 15; x++)
  5.     while (Convert.ToBoolean(Convert.ToInt32(x)))
  6.     {
  7.         do
  8.         {
  9.             Console.WriteLine(1);
  10.             if (Convert.ToBoolean(x >> 1))
  11.             continue;
  12.         }while (Convert.ToBoolean(0));
  13.         break;
  14.     }
  15.     Console.ReadLine();
  16. }

a) 0 0 0….infinite times
b) 1 1 1….infinite times
c) 1 1 1 1 1 1
d) System outofflow exception error

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

  1. static void Main(string[] args)
  2. {
  3.     int x = 0;
  4.     do
  5.     {
  6.         x++;
  7.         if (x == 5)
  8.         {
  9.             x++;
  10.             continue;
  11.             break;
  12.         }
  13.         Console.WriteLine(x + " ");
  14.     }
  15. }while (x < 10);

a) 1 2 3 4 5
b) 10
c) 5 6 7 8 9 10
d) 1 2 3 4 5 6 7 8 9 10

Answer: d

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

  1. static void Main(string[] args)
  2. {
  3.     int x;
  4.     for (x = 1; x <= 3; x++)
  5.     {
  6.         int j = 1;
  7.         do
  8.         {
  9.             j++;
  10.         }while (x % j == 2);
  11.         Console.WriteLine(x + " " + j);
  12.     }
  13.     Console.ReadLine();
  14. }

a) 1 12 1 3 1
b) 1 12 13 1
c) 12 22 32
d) 11 21 31

Answer: c

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