C# Questions & Answers – IF Statements

This section of our 1000+ C# multiple choice questions focuses on relational and logical operators 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 = 30;
  4.      int j = 25 % 25;
  5.      if (Convert.ToBoolean(Convert.ToInt32(i = j)))
  6.      {
  7.          Console.WriteLine("In if");
  8.      }
  9.      else
  10.      {
  11.          Console.WriteLine("In else");
  12.      }
  13.      Console.WriteLine("In main");
  14.      Console.ReadLine();
  15.  }

a) In if
b) In else
c)

In if
In main
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d)

In else
In main
View Answer
Answer: d
Explanation: Usage of ‘=’ operator instead of ‘==’ operator. Hence, the condition is not true.
Output:

         In else
         In main

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

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  1.  static void Main(string[] args)
  2.  {
  3.      int i;
  4.      int b = 8, a = 32;
  5.      for (i = 0; i <= 10; i++)
  6.      {
  7.          if ((a / b * 2)== 2)
  8.          {
  9.              Console.WriteLine( i + " ");
  10.              continue;
  11.          }
  12.          else if (i != 4)
  13.              Console.Write(i + " ");
  14.          else
  15.              break;
  16.     }
  17.     Console.ReadLine();
  18.  }

a) 1 2 3 4 5 6 7 8 9
b) 0 1 2 3 4 5 6 7 8
c) 0 1 2 3
d) 0 1 2 3 4
View Answer

Answer: c
Explanation: The if condition will never be fulfilled as ((a / b) * 2 == 2) is never true. Hence, only else part of condition will be executed until i! = 4 i.e i = 0, 1, 2, 3.
Output:

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0 1 2 3

3. Which of the following conditions are true in the following C# code?

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  1.  static void Main(string[] args)
  2.  {
  3.      Console.WriteLine("Enter a letter:");
  4.      char c = (char)Console.Read();
  5.      if (Char.IsDigit(c) == true)
  6.          Console.WriteLine("A number");
  7.      else if (char.IsLower(c) == true)
  8.          Console.WriteLine("A lowercase letter");
  9.      else if (char.IsUpper(c) == true)
  10.          Console.WriteLine("An uppercase letter");
  11.      Console.ReadLine();
  12.  }
  13.  a. Enter a letter :
  14.     a
  15.     An uppercase letter
  16.  b. Enter a letter :
  17.     A
  18.     An uppercase letter
  19.  c. Enter a letter :
  20.     2
  21.     A number
  22.  d. Enter a letter :
  23.     2
  24.     A lowercase letter.

a) a, b, c
b) b, c, d
c) a, d, b
d) b, c
View Answer

Answer: d
Explanation: None.
Output:

                    Enter a letter :
                          A
                          An uppercase letter
                          Enter a letter :
                          2
                          A number

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

  1.   static void Main(string[] args)
  2.   {
  3.       int i, j;
  4.       for (i = 2; i >= 0; i--)
  5.       {
  6.           for (j = 0; j <= 2; j++)
  7.           {
  8.               if (i == j)
  9.               {
  10.                   Console.WriteLine("1");
  11.               }
  12.               else
  13.               {
  14.                   Console.WriteLine("0");
  15.               }
  16.          }
  17.          Console.WriteLine("\n");
  18.          Console.ReadLine();
  19.       }
  20.   }

a)

   1 0 0
   0 1 0
   0 0 1

b)

   0 1 0
   1 0 0
   0 0 1

c)

   0 0 1
   0 1 0
   1 0 0

d)

   1 0 0
   0 0 1
   0 1 0
View Answer
Answer: c
Explanation: In first row for i = 2 : j = 0 == 0 as if condition fails for (i == j)
i = 2 : j = 1 == 0 as again if condition fails for ( i == j)
i = 2 : j = 2 == 1 as (i == j).
In Second row for i = 1 : j = 0 == 0 as if condition fails for (i == j)
i = 1 : j = 1 == 1 (as i==j)
i = 1 : j = 2 == 0 as (i==j) not true
In Third row for i = 0 : j = 0 == 1 as (i==j) true
i = 0 : j = 1 == 0 as (i==j) not true.
i = 0 : j = 2 == 0 .
So, 0 0 1
0 1 0
1 0 0

Output: 0 0 1
0 1 0
1 0 0

5. Select the correct ‘if statement’ to be filled in the following C# code?

  1.  static void Main(string[] args)
  2.  {
  3.      int []num = {50, 65, 56, 88, 43, 52};
  4.      int even = 0, odd = 0;
  5.      for (int i = 0 ;i < num.Length ;i++)
  6.      {
  7.           /*___________________________*/
  8.      }   
  9.      Console.WriteLine("Even Numbers:" +even);
  10.      Console.WriteLine("Odd Numbers:" +odd);
  11.      Console.ReadLine();
  12.  }

a)

  1.    if ((num % 2) == 0)
  2.    {
  3.        even += 1;
  4.    }
  5.    else
  6.    {
  7.        odd += 1;
  8.    }

b)

  1.    if((num * i) == 0)
  2.    {
  3.        even += 1;
  4.    }
  5.    else
  6.    {
  7.        odd += 1;
  8.    }

c)

  1.    if(num[i] % 2 == 0)
  2.     {
  3.         even += 1;
  4.     }
  5.     else
  6.     {
  7.         odd += 1;
  8.     }

d)

  1.    if(num[i] % 2 = 0)
  2.     {
  3.         even += 1;
  4.     }
  5.     else
  6.     {
  7.         odd += 1;
  8.     }
View Answer
Answer: c
Explanation:

                int []num = {50, 65, 56, 88, 43, 52};
                int even = 0,odd = 0;
                for (int i = 0 ;i &lt; num.Length ;i++)
                {
                    if (num[i] % 2 == 0)
                    {
                    even += 1;
                    }
                    else
                    {
                    odd += 1;
                    }
                }   
                Console.WriteLine("Even Numbers: " +even);
                Console.WriteLine("Odd Numbers: " +odd);
                Console.ReadLine();
 
 

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

  1.  static void Main(string[] args)
  2.  {
  3.      int a = 15, b = 10, c = 1;
  4.      if (Convert.ToBoolean(a) && (b > c))
  5.      {
  6.          Console.WriteLine("cquestionbank");
  7.      }
  8.      else
  9.      {
  10.          break;
  11.      }
  12.  }

a) cquestionbank
b) It will print nothing
c) Compile time error
d) Run time error
View Answer

Answer: c
Explanation: Keyword “break” is not part of if-else statement. This keyword is used in case of loop or switch case statement.

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

  1.   static void Main(string[] args)
  2.   {  
  3.       int a = 5;
  4.       if (Convert.ToBoolean((.002f) -(0.1f)))
  5.       Console.WriteLine("Sachin Tendulkar");
  6.       else if (a == 5)
  7.       Console.WriteLine("Rahul Dravid");
  8.       else
  9.       Console.WriteLine("Ms Dhoni");
  10.       Console.ReadLine();
  11.   }

a) Rahul Dravid
b) Sachin Tendulkar
c) Ms Dhoni
d) Warning : Unreachable Code
View Answer

Answer: b
Explanation: (0.002 – 0.1f) not equivalent to zero hence it is true. So, only first if clause will execute and print:Sachin Tendulkar on console. As, first condition is always true so no else if statement will be executed.
Output:

 Sachin Tendulkar

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

  1.   static void Main(string[] args)
  2.   {   
  3.       int a = -1;
  4.       int b = -1;
  5.       if (Convert.ToBoolean (++a = ++b))
  6.       Console.WriteLine("a");
  7.       else
  8.       Console.WriteLine("b");
  9.       Console.ReadLine();
  10.   }

a) a
b) b
c) Compile time error
d) Code execute successfully with no output
View Answer

Answer: c
Explanation: Both a and b are constants. Illegal to assign a value to constant on left hand of ‘=’operator. Hence, it must be some variable.

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

  1.   static void Main(string[] args)
  2.   {
  3.       int a = 5, b = 10;
  4.       if (Convert.ToBoolean(Convert.ToInt32(0xB)))
  5.       if (Convert.ToBoolean(Convert.ToInt32(022)))
  6.       if (Convert.ToBoolean(Convert.ToInt32('\xeb')))
  7.       Console.WriteLine("java");
  8.       else ;
  9.       else ;
  10.       else ;
  11.   }

a) Compile time error: Misplaced else
b) Compile time error: Undefined symbol
c) java
d) Warning: Condition is always true
View Answer

Answer: c
Explanation:

                  oxB: hexadecimal integer constant.
                  022: It octal integer constant.
                 ‘\xeb’: It is hexadecimal character constant.

As zero is false and any non-zero number is true. All, constants return a non-zero value. So, all if conditions in the above program are true.
Output:

 java.

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

  1.  static void Main(string[] args)
  2.  {
  3.      int a = 5, b = 10;
  4.      if (Convert.ToBoolean(Convert.ToInt32(++a)) || Convert.ToBoolean(Convert.ToInt32(++b)))
  5.      {
  6.          Console.WriteLine(a + "\n" + b);
  7.      }
  8.      else
  9.      Console.WriteLine(" C# ");
  10.  }

a) 6 11
b) 6 16
c) 6 12
d) 6 10
View Answer

Answer: d
Explanation: Consider the following expression:( ++a || ++b). In this expression || is ‘Logical OR operator’. Two important properties of this operator are:
Property 1:
(Expression1) || (Expression2)
|| operator returns 0 if and only if both expressions return a zero otherwise || operator returns 1.
initial value of a is 5. So ++a will be 6. Since ++a is returning a non-zero so ++b will not execute.
Output :

 6 10.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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