10+ algorithm examples with implementation in C programming language

Simple Algorithm Examples

To explain examples of algorithms I used C programming language, you can use your comfortable language

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Algorithm for the addition of array elements

Start
Step 1: initialize sum =0
Step 2: iterate loop from 0 to 9 and increment by 1
Step 3:add sum with each increment
Step 4: print sum
Stop

Implementation in C

#include <stdio.h>
int main()
{
    int arr[10]={1,1,1,1,1,2};
    int i, sum=0;
    for(i=0; i<9; i++)
    {
        sum =sum+ arr[i];
    }
    printf("Sum= %d\n", sum);
    return 0;
}

Output

Sum = 7

Algorithm for array traversal

step 1.[Initialize counter] set k=lower_bound
step 2.Repeat steps 3 and 4 while k<= Upper_bound
step 3.[visit element] Apply a process to A[k]
step 4.[Counter increment] set k=k+1
        [End of loop]
step 5.Exit

Implementation in C

#include <stdio.h>
#include <stdlib.h>
int main()
{
    int k=0;
    int A[9]={10,20,30,40,50,60,70,80,90};
    while(k<=8)
    {
        printf("%d\n",A[k]);
        k=k+1;
    }
    return 0;
}

Output

10 20 30 40 50 60 70 80 90

Algorithm to insert an element in an array

step 1.[Initialize counter] set  J=N-1
step 2.Repeat steps 3 and 4 while J>= pos
step 3.[move j th element down] set  A[J+1]= A[J]
step 4.[Counter Decrement] set J=J-1
          [End of loop]
step 5.[Element insert] set  A[pos]=item
step 6.[Reset N] setN= N+1
step 7.Exit

Implementation in C

#include <stdio.h>
#include <stdlib.h>
int main()
{
    int j, pos=5,item=6, n=8, A[9]={1,2,3,4,5,7,8,9};
    j=n-1;
   while(j>=pos)
   {
    A[j+1]=A[j];
   j=j-1;
   }
   A[pos]=item;
   n=n+1;
   for (j=0;j<n;j++)
    printf("%d",A[j]);
 return 0;
}

Output

1 2 3 4 5 6 7 8 9

Algorithm to Delete an element in an array

step 1.[Initialize counter] set  J=pos
step 2.Repeat steps 3 and 4 while J<= N-1
step 3.[move  j th  element up] set  A[J]= A[J+1]
step 4.[Counter Increment ] set J=J+1
          [END of loop]
step 5.[Reset N] set N= N-1
step 6.Exit

Implementation in C

#include <stdio.h>
#include <stdlib.h>
int main()
{
    int j, pos=5, n=8, A[9]={1,2,3,4,5,7,8,9};
    j=pos;
   while(j<=n-1)
   {
    A[j]=A[j+1];
   j=j+1;
   }
   n=n-1;
   for (j=0;j<n;j++)
    printf("%d",A[j]);
 return 0;
}

Output

1 2 3 4 5 8 9

Algorithm for linear search

step 1.[enter item at the end of A] set  A[N+1]=item
step 2.[initialize counter] set pos=1
step 3.[search for item]
       Repeat while A[pos] != item
       Set pos=pos+1
           [end of loop]
step 4.[successful] if pos =N+1 then set pos =0
step 5.exit

Implementation in C

# include <stdio.h>
int main()
{
    int A[5]={4,5,6,8,9};
    int n=5;
    int item =6;
    A[n+1]=item;
    int pos=1;
    while(A[pos]!=item)
    {
        pos=pos+1;
    }
    if (pos==n+1)
        pos=0;
    printf("pos=%d ",pos);
    return 0;
}

Output

pos=2

Algorithm for finding the length of a string

step 1.[initialize counter] set  J=0
step 2.Repeat step3 while STR[J] != NULL
step 3.[increment the counter] J=J+1
         [end of loop]
step 4.[Set length] length =J 
step 5.exit

Implementation in C

#include <stdio.h>
int main()
{
    char str[80]={"hi iam anees"};
    int j=0, length;
    while(str[j]!= '\0')
    {
        j++;
    length =j;
    }
    printf("length = %d\n",length);
    return 0;
}

Output

length = 12

Algorithm for Extracting a substring from  a string

step 1.[initialize counter] set i=pos, j=0
step 2.Repeat step 3 to 6
        while STR[i] != NULL and N>0
step 3.Set subStr[j]=Str[i]
step 4.[increment the counter] i=i+1
step 5.[increment the counter] j=j+1
step 6.[Reset N] set N=N-1
       [end of loop]
step 7.Set substr[j] =Null
step 8.exit

Implementation in C

# include<stdio.h>
int main()
{
    char str[50]={"hi iam anees"};
    char substr[50]={"anees"};
    int i, j, m=6, n=5;
    i=m;
    j=0;
    while (str[i]!='\0'&& n>0)
    {
        substr[j]=str[i];
        i=i+1;
        j=j+1;
        n=n+1;
    }
    substr[j]='\0';
    puts(substr);
    return 0;
}

Output

anees

Algorithm for inserting a string in the main string

step 1.[initialize counter] set I=0, J=0 and K=0
step 2.Repeat step 3 to 4 while Data[J] != NULL 
step 3.If  I =loc
       Repeat while str[k]!=NULL
        New_data[J]=str[K]
           [increment the counter] J=J+1
           [increment the counter] k=k+1
      [end of  inner loop]
     Else
         New_data[J]=data[I]
            [Increment counter] J=J+1
         [End of if]
step 4.[increment counter] I=I+1
       [End of outer loop]
step 5.Set  new_data[J]=NULL
step 6.Exit

Implementation in C

# include<stdio.h>
int main()
{
    int loc=3, i=0, j=0, k=0;
    char data[50]={"hi  anees"}, str[50]={"i am "},new_data[50];
    while(data[i]!='\0')
    {
        if(i==loc)
        {
            while(str[k]!='\0')
            {
                new_data[j]=str[k];
                j=j+1;
                k=k+1;
                           }
        }
        else
        {
            new_data[j]=data[i];
            j=j+1;
        }
        i=i+1;
    }
    new_data[j]='\0';
    puts(new_data);
    return 0;
}

Output

hi iam anees

Algorithm for Deleting  a substring from the main string

step 1. [initialize counter] set I=0, J=0 
step 2.Repeat step 3 to 6 while Data[I] != NULL 
step 3.If  I =loc
       Repeat while N>0
       [increment counter] I=I+1
          [Reset N] N=N-1
          [End of inner loop]
          [End of if]
step 4.Set New_data[J]=data[I]
step 5.[increment the counter] J=J+1
step 6.[increment counter] I=I+1
        [End of outer loop]
step 7. Set New_data[J]=NULL
step 8.Exit

Implementation in C

# include <stdio.h>
 int main()
 {
     int loc=3,i,j,n=3;
     char Data[50]={"hi iam anees"},new_Data[50]={"iam "};
     i=0;
     j=0;
     while (Data[i]!='\0')
     {
         if(i==loc)
         {
             while(n>0)
             {
                 i=i+1;
                 n=n-1;
             }
         }
         new_Data[j]=Data[i];
         j=j+1;
         i=i+1;
     }
     new_Data[j]='\0';
     puts(new_Data);
     return 0;
 }

Output

hi anees

Algorithm for linked list traversal (or) iteration

Step 1. [initialize pointer p] set p=start
Step 2. Repeat steps 3 and 4 while p!=NULL
Step 3.         Apply the process to p->data
Step 4.        [p now points to the next head] set p= p->next
Step 5.[End of loop]
Step 6.Exit

Implementation in C

#include <stdio.h>
#include <stdlib.h>
struct node
{
    int data;
    struct node *next;
};
int main()
{
    struct node* head_node;
    struct node* second_node;
    struct node* third_node;
    /*allocate memory to 3 nodes */
    head_node =(struct node*)malloc(sizeof (struct node));
    second_node =(struct node*)malloc(sizeof(struct node));
    third_node = (struct node*)malloc(sizeof(struct node));
    head_node->data=1;/*insert data into the head_node */
    head_node->next=second_node;/* link the head_node with second_node*/
    second_node->data=2;
    second_node->next=third_node;
    third_node->data=3;
    third_node->next=NULL;
    struct node *p =head_node;
    while(p!=NULL)
    {
        printf("%d",p->data);
        p=p->next;
    }
    return 0;
}

Output

1 2 3

Algorithm for searching a linked list

Step 1: [initialize pointer p] set p =start
Step 2: Repeat steps 3 and 4 (while p!=NULL)
Step 3: if(item ==p->data)then return (true) :- exit
Step 4:p=p->next
            [End of both if and while loops]
Step 5: exit

Implementation in C

#include <stdio.h>
#include <stdlib.h>
struct node
{
    int data;
    struct node *next;
}* head_node;
void create_linkedlist (int A[],int n)/* function to create linked ist */
{
    int i;
    struct node *temp, *p;/* first node creation */
    head_node =(struct node*)malloc(sizeof(struct node));
    head_node->data=A[0];
    head_node->next=NULL;
    p=head_node;
    for(i=0;i<n;i++)/*rest of the node's created by using loop*/
    {
        temp =(struct node*)malloc(sizeof(struct node));
        temp->data=A[i];
        temp->next=NULL;
        p->next=temp;
        p=temp;
    }
}
void search_linkedlist(struct node *p, int item)
{
    while(p!=NULL)
    {
        if(p->data==item)
        {
            printf("found item");
            exit(0);
        }
        p=p->next;
    }
    printf("not found item");
}
int main()
{
    int A[]={10,20,30,40,50,60,70,80,90};
    create_linkedlist(A,8);/*function call*/
    search_linkedlist(head_node, 10);/* function call*/
    return 0;
}

Output

found item

Algorithm for counting no of elements in a linked list

Step 1.[initializes counter] set N=0
Step 2.[initializes pointer] set p=start
Step 3.Repeat steps  4 and 5 (while p!=NULL)
Step 4.[increment counter] set N=N+1
Step 5.[update pointer] p=p->next;
              [End of loop]
Step 6. Return

Implementation in C

#include <stdio.h>
#include <stdlib.h>
struct node
{
    int data;
    struct node *next;
}* head_node;
void create_linkedlist (int A[],int n)/* function to create linked ist */
{
    int i;
    struct node *temp, *p;/* first node creation */
    head_node =(struct node*)malloc(sizeof(struct node));
    head_node->data=A[0];
    head_node->next=NULL;
    p=head_node;
    for(i=1;i<n;i++)/*rest of the node's created by using loop*/
    {
        temp =(struct node*)malloc(sizeof(struct node));
        temp->data=A[i];
        temp->next=NULL;
        p->next=temp;
        p=temp;
    }
}
void count_linkedlist(struct node *p)
{
    int n;
    n=0;
    while(p!=NULL)
    {
        n=n+1;
        p=p->next;
    }
        {
            printf("no of elements =%d",n);
        }
}
int main()
{
    int A[]={10,20,30,40,50,60,70,80,90};
    create_linkedlist(A,8);/*function call*/
    count_linkedlist(head_node);/* function call*/
    return 0;
}

Output

no of elements =9

Algorithm for the sum of elements in a LinkedList

Step  1.[initialize pointer] set p= head node
Step  2.set sum=0
Step  3.Repeat steps 4 and 5 (while p!=NULL)
Step  4. Set sum=sum+p->data;
Step  5. P=p->next;
                [End of loop]
Step 6. Return sum

Implementation in C

#include <stdio.h>
#include <stdlib.h>
struct node
{
    int data;
    struct node *next;
}* head_node=NULL;
void create_linkedlist (int A[],int n)/* function to create linked ist */
{
    int i;
    struct node *temp, *p;/* first node creation */
    head_node =(struct node*)malloc(sizeof(struct node));
    head_node->data=A[0];
    head_node->next=NULL;
    p=head_node;
    for(i=1;i<n;i++)/*rest of the node's created by using loop*/
    {
        temp =(struct node*)malloc(sizeof(struct node));
        temp->data=A[i];
        temp->next=NULL;
        p->next=temp;
        p=temp;
    }
}
void sum_linkedlist(struct node *p)
{
    int sum;
    sum=0;
    while(p!=NULL)
    {
        sum=sum+p->data;
        p=p->next;
    }
        {
            printf("sum of elements =%d",sum);
        }
}
int main()
{
    int A[]={10,20,30,40,50,60,70,80};
    create_linkedlist(A,8);/*function call*/
    sum_linkedlist(head_node);/* function call*/
    return 0;
}

Output

sum of elements =360

Resource

  • https://www.udemy.com/course/datastructurescncpp/

Mohammed Anees

Hey there, welcome to aneescraftsmanship I am Mohammed Anees an independent developer/blogger. I like to share and discuss the craft with others plus the things which I have learned because I believe that through discussion and sharing a new world opens up

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