Question

Q1: Which of the following is a double-selection control statement?

do…while	for
if…else	if.

Q2: Which of the following is not a Java keyword?

do	next
while	for

Q3: What is output by the following Java code segment?

int temp;

temp = 200;

if ( temp > 90 )

   System.out.println( "This porridge is too hot." );

if ( temp < 70 )

   System.out.println( "This porridge is too cold." );

if ( temp == 80 )

   System.out.println( "This porridge is just right!" );

1. This porridge is too hot.    
2. This porridge is too cold.
3. This porridge is just right!
4. None of the above.

                                            

Conditional Operator (?:)

Q4: Which of the following is not true about the conditional operator ( ?: )?

1. The conditional operator is a ternary operator, meaning that it takes three operands.
2. The first operand is a boolean expression.
3. The second operand is the result value if the condition evaluates to false.
4. The second operand is the result value if the condition evaluates to true.

Q5: What is output by the following Java code segment?

int temp = 50;

if ( temp > 90 )

{

   System.out.println( "This porridge is too hot." );

  

   // cool down

   temp = temp – ( temp > 150 ? 100 : 20 );

} // end if

else

{

   if ( temp < 70 )

   {

      System.out.println("This porridge is too cold.");

           

      // warm up

      temp = temp + (temp < 50 ? 30 : 20);

   } // end if

} // end else

if ( temp == 80 )

   System.out.println( "This porridge is just right!" );

1. This porridge is too hot.
2. This porridge is too cold.
   This porridge is just right!
3. This porridge is just right!
4. None of the above.

Q6: A dangling-else can be clarified by using:

Indentation	Parentheses ()
Braces {}	End-of-line comment //

Q7: The empty statement is denoted with what symbol?

Semicolon ;	Parentheses ()
Braces {}	End-of-line comment //

Q8: Which statement is false?

1. Both syntax errors and logic errors are caught by the compiler.
2. Both syntax errors and logic errors have effects at execution time.
3. Syntax errors are caught by the compiler. Logic errors have effects at execution time.
4. Logic errors are caught by the compiler. Syntax errors have effects at execution time.

Q9: What is output by the following Java code segment?

int temp;

temp = 180;

while ( temp != 80 )

{

   if ( temp > 90 )

   {

      System.out.print( "This porridge is too hot! " );

      // cool down

      temp = temp – ( temp > 150 ? 100 : 20 );

   } // end if

   else

   {

      if ( temp < 70 )

      {

         System.out.print(

            "This porridge is too cold! ");

           

            // warm up

            temp = temp + (temp < 50 ? 30 : 20);

      } // end if

   } // end else

} // end while

if ( temp == 80 )

      System.out.println( "This porridge is just right!" );

1. This porridge is too cold! This porridge is just right!
2. This porridge is too hot! This porridge is just right!
3. This porridge is just right!
4. None of the above.

Answer 1

Q1: -> c. if…else

Eplanation: When the condition is true, it execute some statement and when the condition is false, it execute some other statement.

Q2: -> b. next

Q3: -> a. This porridge is too hot.

Explanation: When the temperature is 200, then only temp > 90 is true and then the statement written under this condition is executed.

Q4: -> c. The second operand is the result value if the condition evaluates to false.

Explanation: The syntax for "?:" conditional operator is given below.

(condition) ? return this if 'condition' is true : return this otherwise

Q5: -> d. None of the above.

Explanation: temp = 50 initially. temp>90 is false, so statement under this condition will not be executed. Then the control will go into else condition. Under else condition, temp<70 is true. So it will print "This porridge is too cold!" and excute the statement "temp = temp + (temp < 50 ? 30 : 20)" which will set the temp to 70. So temp==80 is also false and statements under it will not get excuted. So only "This porridge is too cold!" will be printed.

Q6: -> c. Braces {}

Q7: -> a. Semicolon ;

Explanation: Semicolon actually denotes the end of any statements. If nothing is written before it, then it becomes empty statement.

Q8: -> This question should be  "Which statement is true?".

Ans - c. Syntax errors are caught by the compiler. Logic errors have effects at execution time. This is the only right statement and all others are wrong.

Eplanation: Syntax error happens when you have mistaken in writing the program. It means when you not followed the proper syntax. So at compile time compiler checks for that and will give you the syntax errors made by you. On the other hand logic errors have effect when the program is running(means execution time). Simple example is that you have written a statement to divide and the denominator becomes zero.

Q9: -> b. This porridge is too hot! This porridge is just right!

Explanation: temp = 180 initially. While loop will loop until temp = 80.In the while loop temp > 90 is true so "This porridge is too hot!" will be printed and "temp =  temp – ( temp > 150 ? 100 : 20 );" will be executed which will set temp to 80. Now since the condition in while loop become false, so control will come out of the loop. Now temp == 80 is true, So "This porridge is just right!" will get printed.

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