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

What is the output? class sample4 extends Thread { public static void main(String[] args) { new sample4().start(); } public void run() { try { System.out.println("Starting to wait"); wait(1000); System.out.println("Done waiting, returning back"); } catch(InterruptedException e) { System.out.println("InterruptedException Found"); } catch(Exception e) { System.out.println("Exception found"); } } }

  1. Starting to waitGoes an infinite wait and deadlock

  2. Starting to waitException found

  3. Starting to waitDone waiting, returning back

  4. Starting to waitInterruptedException Found

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Correct choice The wait() method calls without lock so it causes IllegalMonitorStateException, which catch block finds Exception.

Multiple choice

What is the output of the following program? import java.io.*; class sample3 { int a; int b; sample3() { a=0; b=0; } sample3(int b1,int c1) { a=b1; b=c1; } final void print() { System.out.print(a); System.out.print(b); } } class sample31 extends sample3 { int c; sample31() { c=0; } sample31(int c) { this.c=c; super(4,5); } public static void main(String args[]) { sample3 ob1=new sample3(4,5); sample31 ob=new sample31(); System.out.print(ob.a); System.out.print(ob.b); System.out.print(ob.c); sample31 ob2=new sample31(5); System.out.print(ob2.a); System.out.print(ob2.b); System.out.print(ob2.c); }

  1. Cannot call super class constructor Call to the super must be first in the constructor.

  2. 000455

  3. 000005

  4. 000450

  5. 000000
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

super(*) keyword should be the first line constructor, in which it is defined.

Multiple choice

What is the output of the following program? import java.io.*; class sample2 { int a; static int b; sample2() { a=0; b=10; } sample2(int a,int b) { this.a=a; this.b=b; } public void test() { System.out.print(a); System.out.print(b); } public static void main(String args[]) {sample2 ob=new sample2(); System.out.print(ob.a); System.out.print(ob.b); sample2 ob1=new sample2(4,5); System.out.print(ob1.a); System.out.print(ob1.b); test(); } }

  1. 01045010

  2. 0104505

  3. 0104545

  4. error:non static object cannot be referenced from static context

  5. 01045
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

It is the correct choice as it has to create call through object like ob1.test(), without which it is creating an error.

Multiple choice

Which of the following options provides the output of this program, when executed? class Sample5 { private int x, y; public sample5(int x, int y) { x = x; } public String toString() { return "[" + x +" ," + y +" ]"; } public static void main(String []args) { sample5 point = new sample5(10, 20); System.out.println(point); } }

  1. point

  2. Point

  3. [0, 0]

  4. [10, 0]

  5. [10, 20]
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The assignment x = x; inside the construct reassigns the passed parameter. It does not assign the memberx in sample5. The correct way to perform the assignment is this.x = x;. Field y is not assigned, so its value remains 0.

Multiple choice

What is the output of the following program? import static java.lang.System.out; class sample1 { int a; public static void main(String args[]) { System.out.println(a); a++; } }

  1. 0

  2. Error in the importing package

  3. Compile time error

  4. 1

  5. Both 2 and 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Correct choice System class is present in java.lang package. As it is a final class, it calls println() through static printstream object out, so we initially import static java.lang.System.out, which initially declares static object out.

Multiple choice

class sample6 { public static void main(String []args) { Double i = 10.0; Double j = 11.0; Double k = ++i; //INCRSystem.out.println("k == j is" + (k == j)); System.out.println("k.equals(j) is" + k.equals(j)); } } Which of the following options correctly describes the behavior of this program?

  1. When executed, this program printsk == j is falsek.equals(j) is false

  2. When executed, this program printsk == j is truek.equals(j) is false

  3. When executed, this program printsk == j is falsek.equals(j) is true

  4. When executed, this program printsk == j is truek.equals(j) is true

  5. When compiled, the program will result in a compiler error in the line marked with the comment INCR.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Equals () function return true when they have same memory location assigned to it.

Multiple choice

Which of the following options provides the output of this program, when executed? class Sample4 { public static void main(String []args) { String s1 =" Hello Java"; String s2 = new String("Hello Java"); String s3 =" Hello Java"; if(s1 == s2) { System.out.println("s1 and s2 equal"); } else { System.out.println("s1 and s2 not equal"); } if(s1 == s3) { System.out.println("s1 and s3 equal"); } else { System.out.println("s1 and s3 not equal"); } } }

  1. s1 and s2 equal s1 and s3 equal

  2. s1 and s2 equal s1 and s3 not equal

  3. s1 and s2 not equal s1 and s3 not equal

  4. s1 and s2 not equal s1 and s3 equal

  5. None of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

JVM sets a constant pool in which it stores all the string constants used in the type. If two references are declared with a constant, then both refer to the same constant object. The == operator checks the similarity of the objects itself (and not the values in it). Here, the first comparison is between two distinct objects, so we get s1and s2 not equal. On the other hand, since references of s1 and s3 refer to the same object, we get s1 and s3 equal.