While Loop Statements - C# Questions & Answers

This section of our 1000+ C# multiple choice questions focuses on 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, j;
```
```
     for (i = 1; i <= 3; i++)
```
```
     {
```
```
         j = 1;
```
```
         while (i % j == 2)
```
```
         {
```
```
             j++;
```
```
         }
```

         Console.WriteLine(i + " " + j);

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

a) 11 21 31
b) 1 12 13 1
c) 11 21 31
d) 1 1 2 1 3 1
View Answer

Answer: c
Explanation: Since, condition never satisfied for any value of i and j for which (i % j == 2). Hence, j is always constant ‘1’ and ‘i’ increments for i = 1, 2, 3.
Output:

 11 21 31.

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

```
 static void Main(string[] args)
```
```
 {
```
```
     float s = 0.1f;
```
```
     while (s <= 0.5f)
```
```
     {
```
```
         ++s;
```
```
         Console.WriteLine(s);
```
```
     }
```
```
     Console.ReadLine();
```
```
 }
```

a) 0.1
b) 1.1
c) 0.1 0.2 0.3 0.4 0.5
d) No output
View Answer

Answer: b
Explanation: For the first while condition check when s = 0. If it is true as control goes inside loop ++s increments value of s by 1 as 1+0.1 = 1.1. So, for next condition while loop fails and hence, prints final value of s as 1.1.
Output:

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1.1

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

```
 static void Main(string[] args)
```
```
 {
```
```
     int i;
```
```
     i = 0;
```
```
     while (i++ < 5)
```
```
     {
```
```
         Console.WriteLine(i);
```
```
     }
```
```
     Console.WriteLine("\n");
```
```
     i = 0;
```
```
     while ( ++i < 5)
```
```
    {
```
```
        Console.WriteLine(i);
```
```
    }
```
```
    Console.ReadLine();
```
```
}
```

1 2 3 4
1 2 3 4 5

1 2 3
1 2 3 4

1 2 3 4 5
1 2 3 4

1 2 3 4 5
1 2 3 4 5

View Answer

Answer: c
Explanation: For while(i++ < 5) current value of ‘i’ is checked first and hence prints incremented value afterwards. So, i =1, 2, 3, 4, 5. But, for while(++i < 5) current value is incremented first and then checks that value with given condition and hence then prints that value. So, i = 1, 2, 3, 4.
Output:

        1 2 3 4 5
        1 2 3 4

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

```
 static void Main(string[] args)
```
```
 {
```
```
     int x = 0;  
```
```
     while (x < 20)
```
```
     {
```
```
         while (x < 10)
```
```
         {
```
```
             if (x % 2 == 0)
```
```
             {
```
```
                 Console.WriteLine(x);
```
```
             }
```
```
             x++;
```
```
         }
```
```
     }
```
```
     Console.ReadLine();
```
```
 }
```

1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20

b) 0 2 4 6 8 10 12 14 16 18 20
c) 0 2 4 6 8
d) 0 2 4 6 8 10
View Answer

Answer: c
Explanation: Inner while loop condition checks for even number between 0 an 10 and hence prints number between the given range.
Output:

0 2 4 6 8

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

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

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

```
     int c = 1;
```
```
     while (c <= x)
```
```
     {
```
```
         if (c % 2 == 0)
```
```
         {
```

             Console.WriteLine("Execute While " + c + "\t" + "time");

```
         }
```
```
         c++;
```
```
     }
```
```
     Console.ReadLine();
```
```
 }
```
```
for x = 8.
```

   Execute while 1 time
   Execute while 3 time
   Execute while 5 time
   Execute while 7 time

   Execute while 2 time
   Execute while 4 time
   Execute while 6 time
   Execute while 8 time

   Execute while 1 time
   Execute while 2 time
   Execute while 3 time
   Execute while 4 time
   Execute while 5 time
   Execute while 6 time
   Execute while 7 time

   Execute while 2 time
   Execute while 3 time
   Execute while 4 time
   Execute while 5 time

View Answer

Answer: b
Explanation: Checks condition if number is divisible by 2 then it will print it even number times as given for x = 8 so, prints between 2 to 8 times Similarly, for x = 5, Execute 2 and 4 time.
OUTPUT:

        Execute while 2 time.
        Execute while 4 time.
        Execute while 6 time.
        Execute while 8 time.

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

```
  static void Main(string[] args)
```
```
  {
```
```
      int n, r;
```

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

```
      while (n > 0)
```
```
      {
```
```
          r = n % 10;
```
```
          n = n / 10;
```
```
          Console.WriteLine(+r);
```
```
      }
```
```
      Console.ReadLine();
```
```
  }
```
```
 for n = 5432.
```

a) 3245
b) 2354
c) 2345
d) 5423
View Answer

Answer: c
Explanation: Reverse of number using while loop.
Output:

2345.

7. Correct syntax for while statement is:
a)

```
    while
```
```
    {
```
```
 
```
```
 
```
```
 
```
```
     }(condition);
```

```
    while(condition)
```
```
    {
```
```
 
```
```
 
```
```
     };
```

```
    while(condition)
```
```
    {
```
```
 
```
```
 
```
```
     }
```

```
    while(condition);
```
```
    {
```
```
 
```
```
 
```
```
     }
```

View Answer

Answer: c
Explanation: By definition.

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

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

a) 0.05f
b) 1.50f
c) -0.04999995f
d) 1.50f
View Answer

Answer: c
Explanation: for while(i = 1.0f and j = 0.05f). We, had ‘&&’ condition which gives ‘1’. So, control enters while loop. Since, i = 1 and i++ = first execute then increment. So, first with ‘i’ value as 1.0f and ++j = first increment and then executes we had j = 1.05f and Since operation (i++ – ++j) gives us a negative sign number. So, we can stick our choice to option ‘-0.04999995f’ clearly. Now, as i = 2.0f so loop breaks.
Output:

-0.04999995f

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

```
 static void Main(string[] args)
```
```
 {
```
```
     int i = 0;
```
```
     while (i <= 50)
```
```
     {
```
```
         if (i % 10 == 0)
```
```
         continue;
```
```
         else
```
```
         break;
```
```
         i += 10;
```
```
         Console.WriteLine(i % 10);
```
```
    }
```
```
}
```

a) code prints output as 0 0 0 0 0
b) code prints output as 10 20 30 40 50
c) infinite loop but doesn’t print anything
d) Code generate error
View Answer

Answer: c
Explanation: None.

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

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

a) 12 11
b) 10 11
c) 11 10
d) 11 12
View Answer

Answer: c
Explanation: As ++i, first increments then execute so, for ++i i is 11 and j++ is first execute then increments. So, j = 10.
Output:

11 10.

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

```
   static void Main(string[] args)
```
```
   {
```
```
       int i = 1;
```
```
       while (i <= 1)
```
```
       {
```
```
           if ('A' < 'a')
```
```
           {
```

               Console.WriteLine("Hello...");

```
           }
```
```
           else
```
```
           {
```

              Console.WriteLine("Hi...");

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

a) Hi…
b) Hello….
c) Hi…infinite times
d) Hello infinite times
View Answer

Answer: b
Explanation: Ascii value of ‘A’ is 65 and ‘a’ is 97. So, clearly ‘A’ < ‘a’.
Output:

Hello.

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

```
  static void Main(string[] args)
```
```
  {
```
```
      int i = 0;
```
```
      while (i++ != 0) ;
```
```
      Console.WriteLine(i);
```
```
      Console.ReadLine();
```
```
  }
```

a) -127 to +127
b) 0 to 127
c) 1
d) Infinite loop condition
View Answer

Answer: c
Explanation: i++ = first executes then increments as i = 0. So, i++ != 0, which is false clearly as i = 0. Now, control goes inside loop with i = 1. So, statement prints i = 1.
Output:

1.

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