C# Questions & Answers on IF Statements for Freshers

1. Select the output for the following set of 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
d) In else
In main

Answer: d

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

2. Select output for the following set of Code:

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

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:0 1 2 3

3. Select the output for the following set of Code:

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 lower case letter");

9.      else if (char.IsUpper(c) == true)

10.          Console.WriteLine("An upper case letter");

11.      Console.ReadLine();

12.  }

13.  1. Enter a letter :

14.     a

15.     An upper case letter

16.  2. Enter a letter :

17.     A

18.     An upper case letter

19.  3. Enter a letter :

20.     2

21.     A number

22.  4. Enter a letter :

23.     2

24.     A lower case letter.

Which of the following conditions are true ?
a) a ,b ,c
b) b ,c ,d
c) a ,d ,b
d) b ,c

Answer: d

Output:Enter a letter :
A
An upper case letter
Enter a letter :
2
A number

4. Select the output for the following set of 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

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 given set of 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.     }

Answer: c

Explanation: int []num = {50, 65, 56, 88, 43, 52};
int even = 0,odd = 0;
for (int i = 0 ;i < 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 is the output for the following 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

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 is the output for the following 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

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. Select the output for the following set of 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

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.
Output: static void Main(string[] args)
{
int a = -1;
int b = -1;
if (Convert.ToBoolean(++a == ++b))
Console.WriteLine(“a”);
else
Console.WriteLine(“b”);
Console.ReadLine();
}

9. Select the output for the following set of 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

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. Select the output for the following set of 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

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.