Technical Interview Questions: September 2015

What are gradients in CSS3?

What is linear gradient in CSS?

Gradient allows for smooth transitions between colors, which helps to reduce download speed and lowers bandwidth requirements.
It is applicable on the background property.
There are two types of gradient in CSS3: Linear and radial
For linear gradient you must specify 2 colors and direction in which the color. For ex: background: linear-gradient(top, red, blue); //This will make the color change from red to blue starting from top to bottom.
Different directions can be: top, left, right, bottom
Top to bottom is default value for the linear gradient. In that case the definition looks like: linear-gradient(red, blue). If direction is omitted, by default top direction is assumed.
For different browsers linear gradient property is referred as:

-webkit-linear gradient: For Safari
-0-linear gradient: For Opera
-mox-linear gradient: For: For Firefox
linear gradient: For standard syntax

To specify gradient direction as diagonal 2 endpoints are supposed to be mentioned.
For ex: linear-gradient(to bottom right, red, black) //It will move from bottom right starting with red color and gradually change it to black
You can specify angles in the linear gradient as follows: linear-gradient(180deg, red, blue)
You can specify multiple colors too like this: linear-gradient(red, green, blue, black)
Gradient can be made transparent to generate a fading effect. For transparency, rgba function with 0 to 1 can be added.

0 indicates: full transparency
1 indicates: full color and zero transparency.
For ex:

linear-gradient(rgba(255,0,0,0), rgba(255,2,3,1))

What is radial gradient in CSS?

Linear gradient allows you to transform the color from the sides and corners of a shape. However, radial gradient allows you to transform color from center.
It is similar to linear gradient wherein you have to specify at least 2 colors.

For ex: radial-gradient(red, blue)

You can specify different width for the color stops like this: radial-gradient(red 5%, blue 95%) //Red will only occupy 5% and blue will occupy 95%
If you have to repeat the result of a radial gradient across an element then you should use, repeating-radial-gradient.

For ex: repeating-radial-gradient(red, blue 40%, green 35%)

Explain border radius property of CSS3

border-radius property of Css3 allows to give a web page element the looks of rounded corners.

You can specify it like this:

border-radius: 10px

You can specify different radius value for each corner of the element. You can specify 4 values for each corner, 3 values, 2 values, and 1 value for all corner:

If 4 values are specified then 1st, 2nd, 3rd, 4th value will apply to top-left, top-right, bottom-right, bottom-left corner respectively.

For ex: border-radius: 40px, 30px, 20px, 10px; top-left = 40px top-right = 30px bottom-right= 20 px bottom-left = 10px

If 3 values are specified then 1st, 2nd, 3rd value will apply to top-left, top-right, and (bottom-left & bottom-right) respectively. For ex: border-radius: 40px, 30px, 20px;

In above ex: top-left = 40px top-right = 30px bottom-left and bottom-right = 20 px

If 2 values are specified then 1st and 2nd value will apply to following 2 sets respectively. For ex:

border-radius: 40px, 30px;
In above ex: top-left and top-right= 40px bottom-left and bottom-right = 30px

If only value is specified then all corners will have the same value:

For ex: border-radius: 40px;

You can create elliptical corners too:

For ex: border-radius: 40px/20px;

If you have to specify only one border than you can specify it as follows

border-top-left-radius
border-top-right-radius
border-bottom-left-radius
border-bottom-right-radius

Special Features of C Language

Enums

enum shape {circle=10, square, rectangle};

shape a = circle;
shape b = square;
shape c = rectangle;

enum gender {female, male};

The same functionality can be achieved using macros. However, macros have global scope. Enums could have local(Inside a function) or global(if outside of all functions) scope.

Typedef:

struct node
{
 int data;
 node *link;
};

typedef node N;

N *root = new N;
root->data = 10;
root->link = NULL;

cout << root->data << "\t" << root->link;

Bit Fields:

struct employee
{
 unsigned gender: 1; //The colon tells the compiler that we are talking about the bit field
 unsigned id: 4;
 unsigned status: 3;
 unsigned efficient: 2;
};

enum gender {female, mae};
enum id {One,Two};
enum status {Single, Married, Committed};
enum efficient {Yes, No};

int main()
{
 gender gg = female;
 id gi = One;
 status gs = Committed;
 efficient ge = Yes;

 employee e;
 e.gender = gg;
 e.id = gi;
 e.status = gs;
 e.efficient = ge;

 cout << e.gender << endl;
 cout << e.id << endl;
 cout << e.status << endl;
 cout << e.efficient << endl;

 getch();
 return 0;
}

Function Pointers:

void display()
{
 cout << "Display\n";
}

int main()
{ 
 void (*fptr)(); //Pointer to a function
 fptr = display; //Pointer now contains the address of the function
 cout << "Address of the function: " << fptr << endl; //Outputing the address of the function
 (*fptr)(); //Invoking the function; //Invoking the function

 getch();
 return 0;
}

Useful for: Dynamically binding a function to the pointer. Dynamically invoking the function too.

Function returning pointers:

int* display() //This function is returning a pointer.
{
 cout << "Display\n";
 static int i = 30;
 return(&i); //It will actually be returning the address to an integer
}

int main()
{ 
 int *p;
 p = display();//The address is populated in a pointer variable
 cout << "Address : " << p << "\tValue: " << *p;

 getch();
 return 0;
}

Union:

typedef union
{
 int i;
 char c[4];
}test; //This union is not of 8 bytes(4 for int and 4 for chars). It is of 4 bytes only.

int main()
{ 
 test t;
 t.c[0] = 'A'; //The value assigned to the characters will get assigned to the integer i accordingly
 t.c[1] = 'B'; //As the 4 bytes of the characters are shared by the int too. 
 t.c[2] = 'C';
 t.c[3] = 'D'; 
 
 //t.i; // We can't assign value to both the data variables at the same time.
 //This is useful in hardware when sometimes we have to read only 1 value or all the 4 values
 cout << t.c[0] << "\t" << t.c[1] << "\t" << t.c[2] << "\t" << t.c[3] << endl;
 cout << t.i << endl;

 getch();
 return 0;
}

This question can be asked on a phone interview or during a job fair. It gives a quick idea of problem solving skills of the candidate. To find out the absolute of any number, you have to know its concept.

Concept is 'If a number's value is < 0 then its positive equivalent is returned or else the number is returned as it.
For value=0, the number is returned as is' that means 0 is return.

Examples:

If n = -10 then its absolute value will be 10.
If n = 10 then its absolute value will be 10.
If n = 0 then its absolute value will be 0. Following implementation find a number's absolute value.

 
void int findAbsoluteValue(int n)
{
 if(n < 0)
  return n*-1;
 else 
  return n;
}

You might also like:
Find White Spaces in Character Array
Find a character in the String
Number is prime or not
Notes on Sorting and Searching Algorithms
Common String Functions
Reverse a String
Product of all array location expect its own
Find a cycle in the Linked List
Find a binomial co-efficient
Remove duplicates from the array

Telephonic phone technical interview questions

Telephonic phone technical interview questions - Part 2
Counting sort algorithm
B-Tree

Notes on Sorting and searching algorithms

This is a cheat sheet of sorting algorithms concept. It helps to answer the questions on phone interviews. This sheet explains the key difference between different sorting algos.

Sorting

If the no. of elements are small then we can use quadratic algo like: insertion sort
If there are more then 100 elements use: Heapsort, merge sort, quicksort
For items over: 5,000,000 we can use external memory sorting algorithms.
Stable algos maintains ordering in case of duplicates
Nlogn algos are not stable
If the data is partially sorted then insertion sort is better
If the data is uniformly or randomly distributed then bucket or distribution sort makes sense.
If the keys are long strings then it will make sense to use prefix for the intial sort and then use entire key for sorting. Or use Radix sort
If the range of elements is know and it is small. Then we can initialize an n-element bit-vector. Turn on the element that is present. Then scan from L to R and report the true bits.
For sorting requiring using the disk access we can use external sort or

Load the data in a B-Tree and do in-order traversal
Multi-way merge sort

Quicksort optimizations:

Randomize the permutations
b. Median of first, last, and middle element as a the pivot
c. Smaller subsets can use insertion sort. Stop the recursion at the n = 20
d. We use process the smaller partitions before the larger one. This way run-time memory needed will be less. Successive stored calls are at most half as large as the previous one.

Searching

We can use self organizing list, where the most recently accessed elements moves to the front.
The self organizing list can be used when we have multiple access.

You might also like:
Find White Spaces in Character Array
Find a character in the String
Number is prime or not
Finding Absolute Value
Notes on Sorting and Searching Algorithms
Common String Functions
Reverse a String
Product of all array location expect its own
Find a cycle in the Linked List
Find a binomial co-efficient
Remove duplicates from the array

Telephonic phone technical interview questions

Telephonic phone technical interview questions - Part 2
Counting sort algorithm
B-Tree

C++ Basic Concepts

What does a C++ compiler gets from a compiler?

Default assignment operator
Default copy constructor
Default constructor
Default destructor
Size of operator
Assignment Operator2

Virtual Function:

It is a special function that resolves to the most derived version of the function with the same signature.

Example:

Base *p;

Derived d;

p = &d;

In the above example, if the virtual function is defined in derived class d then it will be called otherwise, base class function will be called.

 
class shape {
int x;
int y;


public int findArea(int x, int y) {
   return x*y;
 }
}

class square extends shape {
   int x;
   
   public int findArea(int x) {
       return x*x;
}

class rectangle extends shape {
}

square s = new square();
int x = 10;
int y = 20;

s.findArea(x); //Its own virtual function is called. 
rectangle r = new rectangle();
r.findArea(x,y); //Base Classes virtual function will be called. 

}

What does new keyword do?

It create another instance(new object) of the class. It will allocate space in the memory(heap) for that object;

object o = new object();

Technical Interview Questions

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