Skip to main content

Examples of some common Algorithms of DataStructure in C programming

1.Algorithm to find the average of  a subject marks of ‘N’ number of students.
             AVG_OF_MARKS (LIST, N)
            [LIST is an array containing marks, N is the size of array]
            SUM 0
            Repeat For I=1,2,3, …N
               SUM  SUM  + LIST[i]
            [End of For I]
            AVG SUM/N
            Write: ‘The average is’,AVG

2.Algorithm to find average of SALARY in an array of EMP struct containing information EMPNO, EMPNAME, and SALARY.
        [LIST is an array of EMP, SIZE is size of array]
        SUM 0
        Repeat For I=1,2,3, …SIZE
          SUM SUM  + LIST[I].SALARY
       [End of For I]
       AVG  SUM / SIZE
       Write: ‘The average Salary is’,AVG
An algorithm, that performs sub task, may be called in another algorithm. It is better practice to divide the given problem into sub problems and write the individual algorithms to solve such sub problems and collectively write main algorithm to call the sub algorithms in order to solve the main problem.

3.Algorithm to find maximum of two unequal numbers and use the same to find maximum of four unequal numbers.
          MAX_OF_2(NUM1, NUM2)
          [NUM1 and NUM2 are two numbers]
          If NUM1 > NUM2 Then:
                       Return NUM1
                        Return NUM2
          [End of If]
          MAX_OF_4(NUM1, NUM2, NUM3, NUM4)
          [NUM1, NUM2, NUM3, and NUM4 are numbers]
          TEMP1 MAX_OF_2(NUM1, NUM2)
           TEMP2  MAX_OF_2(NUM3, NUM4)
            MAX MAX_OF_2(TEMP1, TEMP2)
            Return MAX

4.Algorithm to find minimum of two distinct numbers and using the same to find minimum of three distinct numbers.
            MIN_OF_2(NUM1, NUM2)
            [NUM1 and NUM2 are two number]
             If NUM1<NUM2 Then:
                 Return NUM1
                Return NUM2
               [End of If]
               MIN_OF_3(NUM1, NUM2, NUM3)
               [NUM1, NUM2, and NUM3 are distinct number]
                   Return MIN_OF_2(MIN_OF_2(NUM1, NUM2), NUM3)

5.Algorithm to find the GCD (Greatest Common Divisor)
of two positive numbers and use the same to find LCM of two positive numbers.
Rem    NUM1%NUM2 [%Modulus Operator]
Repeat While Rem<>0
  NUM1 <--- NUM2
   NUM2<--- Rem
   Rem <-- NUM1% NUM2
 [End of While]
Return NUM2
  Return(NUM1*NUM2) / GCD (NUM1,NUM2)
Suppose that the LCM algorithm is called using 12 and 16.
The algorithm calls GCD with 12 and 16.

Working of GCD algorithm:
Rem12%16       i.e.  Rem =12
Rem is not equal to Zero. So, NUM1=16 and NUM2=12
Rem16%12       i.e. Rem=4
Rem is not equal to Zero. So, NUM1=12 and NUM2=4
Rem12%4          i.e. Rem=0
Rem is equal to Zero. So, GCD algorithm returns NUM2 that is 4.
When the algorithm LCM gets the result from GCD algorithm it finds the expression value (NUM1 * NUM2) /GCD(NUM1,NUM2).i.e.(12*16) / 4. Which is equal to 48.48 is the LCM of 12 and 16.
Here in this example algorithm, finding LCM is the main problem that can be divided into sub problem like finding the GCD first and using the same to solve the main problem. So, GCD algorithm is written first and in the order algorithm that can be treated as a main algorithm. In this way a given problem can be divided into small problems and algorithms can be written to solve such small problems.

6. Algorithm to find sum of ‘N’ natural numbers between 
N1 and N2.
[N1 and N2 are two different natural numbers]
If N1> N2 Then:
[End of ]
MIN  MIN – 1[to include MIN in sum]
SUM1 (MIN*(MIN +1))/2
SUM2(MAX*(MAX +1))/2
Return SUM2-SUM1
In the above algorithm to find the sum of N natural the formula N(N+1)/2 is used. Instead of formula a repetitive statement can also be used that run from MIN to MAX with setp 1. The algorithm can be re-written as:

[N1 and N2 are two different natural numbers]
If N1>N2 Then:
   MAX N2
   MIN N2
   MAX N2
[End of If]
SUM 0
Repeat For I= MIN, MIN+1, MIN+2 …MAX
    SUMSUM +1 
[End of For]
Return SUM

Dry Run:
Suppose that the above algorithm SUM 1 is called with two number 23 and 11. In the If statement 23>11 condition is TRUE, therefore MAX becomes 23 and MIN becomes 11. Now the loop repeats for 11, 12, 13, 14 up to 23 (I values).Every time when the loop is repeated  I  is added to SUM. So, finally the value of SUM is returned from the algorithm. 


Popular posts from this blog

difference between structure and union in C Language

In c language article we will see the difference between union and structure. Both are the user define datatype in c language. See the table which is mentioned below: ASP.NET Video Tutorial Series Structure Union1.The keywordstruct is used to define a structure 1. The keyword union is used to define a union. 2. When a variable is associated with a structure, the compiler allocates the memory for each member. The size of structure is greater than or equal to the sum ofsizes of its members. The smaller members may end with unused slack bytes. 2. When a variable is associated with a union, thecompiler allocates thememory by considering the size of the largest memory. So, size of union is equal to the size of largest member. 3. Each member within a structure is assigned unique storage area of location. 3. Memory allocated is shared by individual members of union. 4. The address of each member will be in ascending order This indicates that memory for each member will start at different offset v…

Difference between Linear search and Binary Search in c language

SQL Video Channel : Download all SQL Video

Binary Search Linear Search Works only on sorted items. such as  1,2,3,4,5,6  etc
Works on sorted as well as unsorted items. 12,4,5,3,2,1 etc Very efficient if the items are sorted Very efficient if the items are less and present in the beginning of the list. such as Suppose your list items are : 12,3,4,5,1 and you want to search 12 number then you get beginning in the list. Works well with arrays and not on linked lists. Works with arrays and linked lists.
Number of comparisons are less More number of comparisons are required if the items are present in the later part of the array or its elements are more.

Memory representation of Linked List Data Structures in C Language

Memory representation of Linked List

             In memory the linked list is stored in scattered cells (locations).The memory for each node is allocated dynamically means as and when required. So the Linked List can increase as per the user wish and the size is not fixed, it can vary.

               Suppose first node of linked list is allocated with an address 1008. Its graphical representation looks like the figure shown below:

      Suppose next node is allocated at an address 506, so the list becomes,

  Suppose next node is allocated with an address with an address 10,s the list become,

The other way to represent the linked list is as shown below:

 In the above representation the data stored in the linked list is “INDIA”, the information part of each node contains one character. The external pointer root points to first node’s address 1005. The link part of the node containing information I contains 1007, the address of next node. The last node …