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Introduction

A data structure is a particular way of organizing data in a computer so that it can be used effectively.

For example, we can store a list of items having the same data-type using the array data structure.

What is an Algorithm?​

In this tutorial, we will learn what algorithms are with the help of examples.

In computer programming terms, an algorithm is a set of well-defined instructions to solve a particular problem. It takes a set of input and produces a desired output. For example,

An algorithm to add two numbers:

  • Take two number inputs
  • Add numbers using the + operator
  • Display the result

Qualities of Good Algorithms​

  • Input and output should be defined precisely.
  • Each step in the algorithm should be clear and unambiguous.
  • Algorithms should be most effective among many different ways to solve a problem.
  • An algorithm shouldn't include computer code. Instead, the algorithm should be written in such a way that it can be used in different programming languages.

Algorithm Examples​

Algorithm 1: Add two numbers entered by the user​

Step 1: Start
Step 2: Declare variables num1, num2 and sum. 
Step 3: Read values num1 and num2. 
Step 4: Add num1 and num2 and assign the result to sum.
        sum←num1+num2 
Step 5: Display sum 
Step 6: Stop

Algorithm 2: Find the largest number among three numbers​

Step 1: Start
Step 2: Declare variables a,b and c.
Step 3: Read variables a,b and c.
Step 4: If a > b
           If a > c
              Display a is the largest number.
           Else
              Display c is the largest number.
        Else
           If b > c
              Display b is the largest number.
           Else
              Display c is the greatest number.  
Step 5: Stop

Algorithm 3: Find Root of the quadratic equatin ax2 + bx + c = 0​

Step 1: Start
Step 2: Declare variables a, b, c, D, x1, x2, rp and ip;
Step 3: Calculate discriminant
         D ← b2-4ac
Step 4: If D ≥ 0
              r1 ← (-b+√D)/2a
              r2 ← (-b-√D)/2a 
              Display r1 and r2 as roots.
        Else     
              Calculate real part and imaginary part
              rp ← -b/2a
              ip ← √(-D)/2a
              Display rp+j(ip) and rp-j(ip) as roots
Step 5: Stop

What is Data Structure?​

The data structure name indicates itself that organizing the data in memory. There are many ways of organizing the data in the memory as we have already seen one of the data structures, i.e., array in C language. Array is a collection of memory elements in which data is stored sequentially, i.e., one after another. In other words, we can say that array stores the elements in a continuous manner. This organization of data is done with the help of an array of data structures. There are also other ways to organize the data in memory. Let's see the different types of data structures.

The data structure is not any programming language like C, C++, java, etc. It is a set of algorithms that we can use in any programming language to structure the data in the memory.

Major Operations​

The major or the common operations that can be performed on the data structures are:

  • Searching: We can search for any element in a data structure.
  • Sorting: We can sort the elements of a data structure either in an ascending or descending order.
  • Insertion: We can also insert the new element in a data structure.
  • Updation: We can also update the element, i.e., we can replace the element with another element.
  • Deletion: We can also perform the delete operation to remove the element from the data structure.

Advantages of Data structures​

The following are the advantages of a data structure:

  • Efficiency: If the choice of a data structure for implementing a particular ADT is proper, it makes the program very efficient in terms of time and space.
  • Reusability: The data structure provides reusability means that multiple client programs can use the data structure.
  • Abstraction: The data structure specified by an ADT also provides the level of abstraction. The client cannot see the internal working of the data structure, so it does not have to worry about the implementation part. The client can only see the interface.