Do While Loop Statements - C# Questions & Answers

This section of our 1000+ C# multiple choice questions focuses on do while loop statements in C# Programming Language.

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

```
 static void Main(string[] args)
```
```
 {
```
```
     int i = 1, j = 2, k = 3;
```
```
     do
```
```
     {
```

         Console.WriteLine((Convert.ToBoolean(Convert.ToInt32(i++)))

         && (Convert.ToBoolean(Convert.ToInt32(++j))));

```
     }while (i <= 3);
```
```
     Console.ReadLine();
```
```
 }
```

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

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

True True True

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

```
static void Main(string[] args)
```
```
{
```
```
    float i = 1.0f, j = 0.05f;
```
```
    do
```
```
    {
```
```
        Console.WriteLine(i++ - ++j);
```
```
    }while (i < 2.0f && j <= 2.0f);
```
```
    Console.ReadLine();
```
```
}
```

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

Answer: d
Explanation: None.
Output :

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 -0.04999995

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

```
static void Main(string[] args)
```
```
{
```
```
    int i = 1, j = 5;
```
```
    do
```
```
    {
```
```
        Console.WriteLine(i = i++ * j);
```
```
    }while (i <= 10);
```
```
    Console.ReadLine();
```
```
}
```

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
View Answer

Answer: b
Explanation: 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:

5 25.

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

```
 static void Main(string[] args)
```
```
 {
```
```
     int i = 1234 ,j = 0;
```
```
      /*ADD CODE HERE */
```
```
     Console.WriteLine(j);
```
```
 }
```

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

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

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

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

View Answer

Answer: a
Explanation: None.
Output :

static void Main(string[] args)
        {
              int i = 1234,j = 0;
              do
              {
                  j = j +( i % 10);
 
              }while ((i = i / 10)!= 0);
              Console.WriteLine(j);

}

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

```
 static void Main(string[] args)
```
```
 {
```
```
     long  x;
```

     x = Convert.ToInt32(Console.ReadLine());

```
     do
```
```
     {
```
```
         Console.WriteLine(x % 10);
```
```
     }while ((x = x / 10) != 0);
```
```
     Console.ReadLine();
```
```
 }
```
```
 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’
View Answer

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

 4321.

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

```
 static void Main(string[] args)
```
```
 {
```
```
     int i, s = 0, a = 1, d;
```

     i = Convert.ToInt32(Console.ReadLine());

```
     do
```
```
     {
```
```
         d = i % (2 * 4);
```
```
         s = s + d * a;
```

     }while ((Convert.ToInt32(i = i / (2 * 4))) != 0

      && (Convert.ToBoolean(Convert.ToInt32((a) = (a * 10)))));

```
     Console.WriteLine(s);
```
```
     Console.ReadLine();
```
```
 }
```
```
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
View Answer

Answer: b
Explanation: None.
Output :

         i = 342.
         s = 526.

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

   do;
   {
    statement;
   }while (condition);

   do(condition)
   {
     statement;
   }while;

   do
   {
     statement;
   }while (condition)

   do
   {
        statement;
   }while (condition);

View Answer

Answer: d
Explanation: By definition
Output:

do
       {
          statement;
        }while (condition);

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

```
static void Main(string[] args)
```
```
{
```
```
    int x = 10;
```
```
    do
```
```
    {
```
```
        Console.WriteLine( x++);
```
```
    }
```

    while(Convert.ToBoolean(5) && Convert.ToBoolean(4) && Convert.ToBoolean(3)

    && Convert.ToBoolean(2) && Convert.ToBoolean(1) && Convert.ToBoolean(0));

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

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

Answer: d
Explanation: Here in do while condition ‘&&’ i.e ‘AND’operator return ‘0’ i.e false. So, as condition is false so program comes out of the loop.
Output :

10.

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

```
static void Main(string[] args)
```
```
{
```
```
    int x;
```
```
    for (x = 10; x <= 15; x++)
```

    while (Convert.ToBoolean(Convert.ToInt32(x)))

```
    {
```
```
        do
```
```
        {
```
```
            Console.WriteLine(1);
```

            if (Convert.ToBoolean(x >> 1))

```
            continue;
```
```
        }while (Convert.ToBoolean(0));
```
```
        break;
```
```
    }
```
```
    Console.ReadLine();
```
```
}
```

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

Answer: c
Explanation: The execution of for loop is done for six consecutive times.
Output :

1 1 1 1 1 1

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

```
static void Main(string[] args)
```
```
{
```
```
    int x = 0;
```
```
    do
```
```
    {
```
```
        x++;
```
```
        if (x == 5)
```
```
        {
```
```
            x++;
```
```
            continue;
```
```
            break;
```
```
        }
```
```
        Console.WriteLine(x + " ");
```
```
    }
```
```
}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
View Answer

Answer: d
Explanation: The condition will print the numbers from 1 to 10 when x == 5 and when x does not satisfy if condition until x < 10.
Output:

1 2 3 4 5 6 7 8 9 10

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

```
static void Main(string[] args)
```
```
{
```
```
    int x;
```
```
    for (x = 1; x <= 3; x++)
```
```
    {
```
```
        int j = 1;
```
```
        do
```
```
        {
```
```
            j++;
```
```
        }while (x % j == 2);
```
```
        Console.WriteLine(x + " " + j);
```
```
    }
```
```
    Console.ReadLine();
```
```
}
```

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

Answer: c
Explanation: None.
Output :

 12 22 32

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