Computer Knowledge

Programming Output Evaluation

1,953 Questions

Programming output evaluation tests the ability to trace code execution in languages like C, Java, and SAS. It focuses on arrays, loops, pointers, and data type conversions. These technical questions are standard in computer knowledge sections for IT officer and bank exams.

Java string bufferC language pointersLoop execution outputsData type conversionsMacro variable evaluation

Programming Output Evaluation Questions

Multiple choice php

What is displayed when the following script is executed?

define(myvalue, "10");
$myarray[10] = "Dog";
$myarray[] = "Human";
$myarray['myvalue'] = "Cat";
$myarray["Dog"] = "Cat";
print "The value is: ";
print $myarray[myvalue]."\\n";

  1. The value is: Dog

  2. The value is: Cat

  3. The value is: Human

  4. The value is: 10
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The constant 'myvalue' is defined as '10'. In '$myarray[myvalue]', PHP uses the constant's value, accessing '$myarray[10]'. Since '$myarray[10]' was assigned the string 'Dog', the output is 'The value is: Dog'. The later assignment to the string key 'myvalue' does not affect this.

Multiple choice php

What is the value of $result in the following PHP code?

function timesTwo($int)
{
  $int = $int * 2;
}

$int = 2;

$result = timesTwo($int);

  1. 0

  2. 2

  3. 4

  4. NULL
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the provided code, the function 'timesTwo' modifies a local copy of the variable '$int'. It does not use a return statement to send a value back to the caller. Consequently, when '$result = timesTwo($int)' is executed, the variable '$result' is assigned NULL.

Multiple choice php

Which of the following snippets prints a representation of 42 with two decimal places?



    


    

      
    
          
  1. 
            
    printf("%.2d\n", 42);
    
    
          
    2. 
          
  2. 
            
    printf("%1.2f\n", 42);
    
    
          
    3. 
          
  3. 
            
    printf("%1.2u\n", 42);
    
    
          
    4. 
          
  4. 
            
    none of the above
    
    
          
    5. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        B
        Correct answer
      

        

          Explanation
          

            
The '%f' specifier is used for floating-point numbers. In printf, '%1.2f' tells PHP to treat the input as a float and display it with at least one digit before the decimal and exactly two digits after. Even though 42 is an integer, it is cast to 42.00.


          

        

    

  



      


    


    

      Multiple choice
        
              java

        
    


    

        
What is output of the above program?



class conditional {
 public static void main(String args[]) {
   int i = 20;
   int j = 55;
   int z = 0;
   z = i < j ? i : j; // ternary operator
   System.out.println("The value assigned is " + z);
 }
}



    


    

      
    
          
  1. 
            
    The value assigned is 20
    
    
          
    2. 
          
  2. 
            
    The value assigned is 60
    
    
          
    3. 
          
  3. 
            
    The value assigned is 30
    
    
          
    4. 
          
  4. 
            
    The value assigned is 50
    
    
          
    5. 
          
  5. 
            
    The value assigned is 40
    
    
          
    6. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        A
        Correct answer
      

        

          Explanation
          

            
The ternary operator evaluates the condition (i < j). Since 20 is less than 55, the condition is true. The operator returns the first value after the question mark, which is 'i' (20). Therefore, z becomes 20, and the program prints 'The value assigned is 20'.


          

        

    

  



      


    


    

      Multiple choice
        
              java

        
    


    

        
What is the output of following piece of code ?



int x = 2;
 switch (x) {
 case 1:System.out.println("1?);
 case 2:
 case 3:System.out.println("3?);
 case 4:
 case 5:System.out.println("5?);
 }



    


    

      
    
          
  1. 
            
    No output
    
    
          
    2. 
          
  2. 
            
    3 and 5
    
    
          
    3. 
          
  3. 
            
    1, 3 and 5
    
    
          
    4. 
          
  4. 
            
    3
    
    
          
    5. 
      

    


    

      Reveal answer
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        B,D
        Correct answer
      

        

          Explanation
          

            
To solve this question, the user needs to understand the concept of switch case statements in Java. The switch statement tests the value of a variable and compares it with multiple cases. If a case matches the value of the variable, then the code inside that case is executed. If no matching cases are found, then the default case is executed.



In the given code, the variable x is initialized to 2. The switch statement checks the value of x, and since it matches the case 2, the code inside that case is executed. Since there are no break statements, the control falls through to the next case, which is 3. Thus, the output will be "3?".



The case for 1 and 5 are not executed because the value of x is not equal to 1 or 5. 



Option A is incorrect because there is output from the code. Option B is incorrect because the output is not just 3 and 5. Option C is incorrect because there is no output for 1.



Therefore, the answer is:



The Answer is: D. 3


          

        

    

  



      


    


    

      Multiple choice
        
              java

        
    


    

        
A Vector is declared as follows. What happens if the code tried to add 6 th element to this Vector new vector(5,10)


    


    

      
    
          
  1. 
            
    The element will be successfully added
    
    
          
    2. 
          
  2. 
            
    ArrayIndexOutOfBounds Exception
    
    
          
    3. 
          
  3. 
            
    The Vector allocates space to accommodate up to 15 elements
    
    
          
    4. 
          
  4. 
            
    none of these
    
    
          
    5. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        A,C
        Correct answer
      

        

          Explanation
          

            
The constructor new Vector(5, 10) creates a Vector with an initial capacity of 5 and a capacity increment of 10. Adding a 6th element exceeds the initial capacity, triggering the Vector to grow. It will allocate space for 5 + 10 = 15 elements and successfully add the item.


          

        

    

  


    



      


    


    

      Multiple choice
        
              java

        
    


    

        
HashMap is thread-safe whereas Hashtable is not10, Which of the following assignment statements is invalid?


    


    

      
    
          
  1. 
            
    double D = 45456.444;
    
    
          
    2. 
          
  2. 
            
    long L = 45784;
    
    
          
    3. 
          
  3. 
            
    int I = L;
    
    
          
    4. 
          
  4. 
            
    int J = (int) D;
    
    
          
    5. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        C
        Correct answer
      

        

          Explanation
          

            
Java requires explicit casting when assigning a larger type (like long or double) to a smaller type (like int) because of potential data loss. Assigning a long to an int directly (Option C) is a compile-time error without a cast. Option D is valid because it uses an explicit cast.


          

        

    

  



      


    


    

      Multiple choice
        
              java

        
    


    

        
What will happen when you attempt to compile and run the following code




public class Hope{
    public static void main(String argv[]){
        Hope h = new Hope();
    }
    protected Hope(){
        for(int i =0;
        i &lt;10;
        i ++){
            System.out.println(i);
        }
    }
}



    


    

      
    
          
  1. 
            
    Compilation and running with output 0 to 9
    
    
          
    2. 
          
  2. 
            
    Run time error: Constructors cannot be declared protected
    
    
          
    3. 
          
  3. 
            
    Compilation error: Constructors cannot be declared protected
    
    
          
    4. 
          
  4. 
            
    Compilation and running with output 0 to 10
    
    
          
    5. 
          
  5. 
            
    None of the above
    
    
          
    6. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        A
        Correct answer
      

        

          Explanation
          

            
The class has a main method creating an instance of Hope. The constructor is protected. Since the instantiation happens within the same class (Hope), the protected modifier allows access. The loop runs from 0 to 9 (since i < 10), printing 0 to 9.


          

        

    

  



      


    


    

      Multiple choice
        
              java

        
    


    

        
What is output of the above program?



Class conditional {
 public static void main(String args[]) {
  int i = 20;
  int j = 55;
  int z = 0;
  z = i &lt; j ? i : j; // ternary operator
  System.out.println("The value assigned is " + z);
 }
}



    


    

      
    
          
  1. 
            
    20
    
    
          
    2. 
          
  2. 
            
    55
    
    
          
    3. 
          
  3. 
            
    None of the above
    
    
          
    4. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        A
        Correct answer
      

        

          Explanation
          

            
The ternary operator checks if i (20) is less than j (55). This is true. Therefore, the expression evaluates to i, which is 20. The value 20 is assigned to z.


          

        

    

  



      


    


    

      Multiple choice
        
              java

        
    


    

        
Following code will result in:



int a1 = 5; 
double a2 = (float)a1;



    


    

      
    
          
  1. 
            
    Compilation error
    
    
          
    2. 
          
  2. 
            
    Runtime error
    
    
          
    3. 
          
  3. 
            
    No errors
    
    
          
    4. 
          
  4. 
            
    Execptions
    
    
          
    5. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        C
        Correct answer
      

        

          Explanation
          

            
The code casts an int to float, then assigns to double. This is valid - int can be implicitly converted to float, and float can be implicitly converted to double ( widening conversions). No compilation or runtime error occurs.


          

        

    

  



      


    


    

      Multiple choice
        
              java

        
    


    

        
Following code will result in:



class A {
  int b = 1;
  public static void main(String [] args) {
       System.out.println("b is " + b);
 }
}



    


    

      
    
          
  1. 
            
    Compilation error
    
    
          
    2. 
          
  2. 
            
    Runtime Error
    
    
          
    3. 
          
  3. 
            
    Runtime Exception
    
    
          
    4. 
          
  4. 
            
    Output of b is 1
    
    
          
    5. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        A
        Correct answer
      

        

          Explanation
          

            
The variable b is an instance variable (non-static), but main() is a static method. Static methods cannot access instance variables directly without creating an object instance first. This causes a compilation error.


          

        

    

  


    



      


      


    


    

      Multiple choice
        
              java

        
    


    

        
Following code will result in: int a = 3.5;


    


    

      
    
          
  1. 
            
    Compilation error
    
    
          
    2. 
          
  2. 
            
    Runtime error
    
    
          
    3. 
          
  3. 
            
    a being 3.5
    
    
          
    4. 
          
  4. 
            
    a being 3.
    
    
          
    5. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        A
        Correct answer
      

        

          Explanation
          

            
To solve this question, the user needs to have an understanding of variable types and type casting in programming.



Explanation for each option:



A. Compilation error: This option is correct. In many programming languages, including Java, assigning a floating-point value (such as 3.5) to an integer variable (such as int a) will result in a compilation error. This is because the two types are not compatible, and an explicit type casting is required.



B. Runtime error: This option is incorrect. Runtime errors occur when a program is executed and encounters an error, but in this case, the error would be caught by the compiler during the compilation phase.



C. a being 3.5: This option is incorrect. As mentioned earlier, assigning a floating-point value to an integer variable will result in a compilation error. The value 3.5 cannot be stored in an int variable.



D. a being 3: This option is incorrect. Since the value 3.5 cannot be stored in an int variable, the value of a will not be 3. The code will not compile, so no value will be assigned to a.



Therefore, the correct answer is:



A. Compilation error


          

        

    

  



      


    


    

      Multiple choice
        
              java

        
    


    

        
Following code will result in: int a1 = 5; double a2 = (float)a1;


    


    

      
    
          
  1. 
            
    Compilation error
    
    
          
    2. 
          
  2. 
            
    Runtime error
    
    
          
    3. 
          
  3. 
            
    No errors
    
    
          
    4. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        C
        Correct answer
      

        

          Explanation
          

            
To solve this question, the user needs to understand the concept of type casting and data types in programming.



The given code snippet initializes an integer variable a1 with the value 5 and then assigns that value to a double variable a2 after performing a type casting to a float.



Now, let's go through each option and explain why it is right or wrong:



A. Compilation error: This option is incorrect. The code will compile without any errors because type casting from an integer to a float is allowed in most programming languages.



B. Runtime error: This option is incorrect. The code will not result in a runtime error because the type casting from an integer to a float is allowed and will not cause any issues at runtime.



C. No errors: This option is correct. The code will execute without any errors, and the value 5 will be successfully assigned to the a2 variable after the type casting.



Therefore, the correct answer is: C. No errors.


          

        

    

  



      


    


    

      Multiple choice
        
              java

        
    


    

        
Following code will result in: int a = 9/0;


    


    

      
    
          
  1. 
            
    Compilation error: Divisions must be in a try block.
    
    
          
    2. 
          
  2. 
            
    Compilation error: DivideByZeroException
    
    
          
    3. 
          
  3. 
            
    Runtime Exception
    
    
          
    4. 
          
  4. 
            
    No Error: a is NaN
    
    
          
    5. 
      

    


    

      Reveal answer
      Fill a bubble to check yourself
    


    

      

        C
        Correct answer
      

        

          Explanation
          

            
Integer division by zero is not a compile-time error because the compiler cannot always determine the divisor's value at compile time. At runtime, dividing an integer by zero throws a runtime exception (DivideByZeroException in languages like C# and Java). Floating-point division would return NaN, but integer types don't support NaN.