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vindhya Hegde

Posted on

# Most Frequently asked Coding Questions

Here I will be mainly focusing on OnCampus technical Interviews because I have attended a couple of them. and I observed these are common questions to check you know the basics of coding or not.

#### 1.To swap two numbers without using an extra variable

``````import java.util.*;
public class Main
{
public static void main(String[] args)
{
int a,b;
System.out.println("Enter two numbers");
Scanner sc = new Scanner(System.in);
a = sc.nextInt();
b = sc.nextInt();
//logic to swap without using extra variable.
a = a+b;
b = a - b;
a = a - b;
System.out.println("After swapping: "+ "a="+ a +"," + "b="+ b );
}
}

``````

#### 2.Check given number is Amstrong Number or not

``````import java. util.*;
public class Main
{
public static void main(String[] args)
{
int a;
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number");
a = sc.nextInt();
//to find length or number of digits in number
int num = a;
int len = 0;
int rem;
while(num!=0)
{
rem = num%10;
num = num/10;
len++;
}
//logic to check Armstrong number or Not

int sum = 0;
num = a;
while(num!=0)
{
rem = num%10;
int mul= 1;
for(int i=0;i<len;i++)
{
mul = mul * rem;
}
sum +=mul;
num= num/10;
}
if(sum==a)
{
System.out.println("Amstrong Number");
}
else{
System.out.println("Not an Amstrong number");
}
}
}

``````

#### 3.To find out the Fibonacci value

``````import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
int n;
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number");
n = sc.nextInt();
int n1 = 0 , n2 = 1;
int res = 0;
for(int i=2;i<=n;i++)
{
res = n1+n2;
n1 = n2;
n2 = res;
}
System.out.println("Fib of n is " + res);

}
}

``````

#### 4.to print Fibonacci series

``````import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
int n;
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number");
n = sc.nextInt();
int n1 = 0 , n2 = 1;
int res = 0;
System.out.print("Fibonacci series is " + n1 + " " + n2 + " ");
for(int i=2;i<=n;i++)
{
res = n1+n2;
n1 = n2;
n2 = res;
System.out.print(res + " ");
}

}
}

``````

#### 5.Factorial of a number

``````import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
int n;
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number");
n = sc.nextInt();
int fact = 1;
for(int i=1;i<=n;i++)
{
fact = fact * i;
}
System.out.println("Factorial of n is:" + fact);

}
}

``````

#### 6.LCM and GCD of a number

``````import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
int n1,n2;
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number");
n1 = sc.nextInt();
n2 = sc.nextInt();
int numerator,denominator;
if(n1>n2)
{
numerator = n1;
denominator = n2;
}
else{
numerator = n2;
denominator = n1;
}
int rem = numerator%denominator;
while(rem!=0)
{
numerator = denominator;
denominator = rem;
rem = numerator%denominator;
}
System.out.println("HCF of numbers:" + denominator );
int lcm = (n1*n2)/denominator;
System.out.println("LCM of numbers:" + lcm );
}
}

``````

#### 7.Program to check leap year or not

``````import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
int n1,n2;
Scanner sc = new Scanner(System.in);
System.out.println("Enter the year");
int year = sc.nextInt();
if(year%4==0)
{
//check for century year
if(year%100==0)
{
//check it is divisible by 400
if(year%400==0)
{
System.out.println("Leap year");
}
else{
System.out.println("Not a leap year");
}
}
else{
System.out.println("Leap year");
}
}
else{
System.out.println("Not a leap year");
}

}
}

``````

I hope this helps for your OnCampus technical Interviews.

## Discussion (6)

Leonid Medovyy

A. I think it’s super cool that you are sharing this. I’m sure it will help people interviewing.

B. Not related to you, but I’m generally confused why anyone would test a candidates ability to creatively solve problems by having them swap out variables without using a placeholder or printing out a Fibonacci sequence.

ad B) simple "follow the herd" principle applied by companies doing those interviews ;) and in return they'll get the candidates who most diligently rote memorized the questions and the answers

yes I shudder at all of this, so glad they never made me go through this kind of nonsense when I took my first steps as a junior ... customers pay us to solve their problems, not to generate Fibonacci numbers

vindhya Hegde

Jay Jeckel • Edited on

1.To swap two numbers without using an extra variable

I often ask this when doing interviews and I reject any candidate that doesn't point out that swapping two variables without using a temp variable is extremely bad practice and should never, never, never, never, never, never be done in a real project.

7.Program to check leap year or not

Likewise, the correct answer to this question is that dates are non-trivial and built-in packages should be used for any date handling or manipulation; one shouldn't be rolling their own logic for such things.

EDIT: I just noticed who the author is and I have to say I'm glad you are writing more articles. I love your vocabulary building series. :)

vindhya Hegde