1. Sort a given list of strings.

#include<string.h>
void main()
{
int i,j,count;
char str[20][20],temp[20];
printf("enter the no. of string: ");
scanf("%d",&count);
printf("enter strings one by one: \n");
for(i=0;i<=count;i++)
gets(str[i]);
for(i=0;i<=count;i++){
for(j=i+1;j<=count;j++){
if(strcmp(str[i],str[j])>0)
{
strcpy(temp,str[i]);
strcpy(str[i],str[j]);
strcpy(str[j],temp);
}}}
printf("\n sorted string:");
for(i=0;i<=count;i++)
puts(str[i]);
return 0;
}

2. Insertion and deletion operation in an array.

#include <stdio.h>

#include <stdlib.h>

int main()

int a[100];

int element,i,loc,size,n=0,j=0;

printf("Enter the size of an array\n");

scanf("%d",&size);

printf("Enter %d array elements\n",size);

for(i=0;i<size;i++)

scanf("%d",&a[i]);

}
 printf("List before Insertion: ");

for(i=0;i<size;i++)

printf("%d ",a[i]);

printf("\nEnter an element to insert\n");

scanf("%d",&element);

printf("Enter a position to insert an element %d\n",element);

scanf("%d",&loc);

loc--;

for(i=size-1;i>=loc;i--)

a[i+1]=a[i];

a[loc]=element;

printf("\nList after Insertion: ");

for(i=0;i<size+1;i++)

printf("%d ",a[i]);

printf("\nEnter an element to delete\n");

scanf("%d",&n);

i=0;

for(i=0;i<size;i++)

if(a[i]==n)

for(j=i;j<(size-1);j++)

a[j]=a[j+1];

}
 break;

printf("List after deletion\n");

for(i=0;i<(size-1);i++)

printf("%d ",a[i]);

return 0;

3. Search an element in the 2-dimensional array.

#include<stdio.h>

int main(){

int m, n, item, count=0, array[10][10];

printf("Enter the number of rows and columns: ");

scanf("%d %d", &m, &n);

printf("Enter %d elements: ", (m*n));

for(int i=0; i<m; i++){

for(int j=0; j<n; j++){

scanf("%d", &array[i][j]);

printf("Enter the item to find: ");

scanf("%d", &item);

for(int i=0; i<m; i++){

for(int j=0; j<n; j++){

if(array[i][j] == item){

printf("Item found at [%d, %d] \n", i, j);

count++;

}
 }

if(count==0)

printf("Item Not found");

return 0;

4. Implement Pattern matching algorithm.

#include <stdio.h>

#include <string.h>

int main()

char text[20],pat[20];

int a,b;

printf("Enter the string : ");

gets(text);

printf("Enter the pattern to find : ");

gets(pat);

a = strlen(pat);

b = strlen(text);

for (int i = 0; i <= b - a; i++) {

int j;

for (j = 0; j < a; j++)

if (text[i + j] != pat[j])

break;

if (j == a)

printf("Pattern found at position %d \n", i+1);

}
 return 0;

5. Append 2 arrays.

#include<stdio.h>

#include<string.h>

int main() {

int a[20],b[20],c[40],a_len,b_len,i,j,k,m,n;

printf("Enter number of elements in first array : ");

scanf("%d",&m);

printf("Enter the elements : ");

for(i = 0; i < m; i++) {

scanf("%d",&a[i]);

printf("Enter number of elements in second array : ");

scanf("%d",&n);

printf("Enter the elements : ");

for(i = 0; i < n; i++) {

scanf("%d",&b[i]);

for(i = 0; i < m; i++) {

c[i]=a[i];

for(j = 0; j < n; j++) {

c[j+m]=b[j];

printf("Array one ");

for(i=0;i<m;i++){

printf("%d ",a[i]);
 }

printf("\n");

printf("Array two ");

for(i=0;i<n;i++){

printf("%d ",b[i]);

printf("\n");

printf("Arrays after appending : ");

for(i=0;i<m+n;i++){

printf("%d ",c[i]);

return 0;

6. Search an element in the array using linear search.

#include <stdio.h>

void main()

int num;

int i, key, element_found = 0;

printf("Enter number of elements you would like to take as input: ");

scanf("%d", &num);

int arr[num];

printf("\nEnter all the elements of your choice:");

scanf("%d", &arr[i]);

printf("\nEnter the key element that you would like to be searched: ");

scanf("%d", &key);

for (i = 0; i < num ; i++)

if (key == arr[i] )

element_found = 1;

break;

if (element_found == 1)
 printf("we got the element at index %d",i+1);

else

printf("we haven’t got element at any index in the array\n");

7. Search an element in the array using binary search.

int main()

int c, first, last, middle, n, search, array[100];

printf("Enter number of elements\n");

scanf("%d",&n);

printf("Enter %d integers\n", n);

for ( c = 0 ; c < n ; c++ )

scanf("%d",&array[c]);

printf("Enter value to find\n");

scanf("%d",&search);

first = 0;

last = n - 1;

middle = (first+last)/2;

while( first <= last )

if ( array[middle] < search )

first = middle + 1;

else if ( array[middle] == search )

printf("%d found at location %d.\n", search, middle+1);

break;

}
 else

last = middle - 1;

middle = (first + last)/2;

if ( first > last )

printf("Not found! %d is not present in the list.\n", search);

return 0;

8. Read a sparse matrix and display its triplet representation using array.

#include<stdio.h>

int main()

int S[10][10],m,n,i,k=0,size=0;

printf("Enter number of rows in the matrix : ");

scanf("%d",&m);

printf("Enter number of columns in the matrix : ");

scanf("%d",&n);

printf("Enter elements in the matrix : ");

for (int i = 0; i < m; i++)

for (int j = 0; j < n; j++)

scanf("%d",&S[i][j]);

printf("The matrix is \n");

for (int i = 0; i < m; i++) {

for (int j = 0; j < n; j++) {

printf(" %d ",S[i][j]);

if (S[i][j] != 0)

size++;

printf("\n");

int M[3][size];
 for (int i = 0; i < m; i++)

for (int j = 0; j < n; j++)

if (S[i][j] != 0)

M[0][k] = i;

M[1][k] = j;

M[2][k] = S[i][j];

k++;

printf("Triplet representation of the matrix is \n");

for (int i=0; i<3; i++)

for (int j=0; j<size; j++)

printf(" %d ", M[i][j]);

printf("\n");

return 0;

9. Create a singly linked list of n nodes and display it.

#include <stdio.h>

#include <stdlib.h>

struct node {

int num;

struct node *nextptr;

} *stnode;

void createNodeList(int n);

void displayList();

int main() {

int n;
 printf("\n\n Linked List : To create and display Singly Linked List :\n");

printf("-------------------------------------------------------------\n");

printf(" Input the number of nodes : ");

scanf("%d", &n);

createNodeList(n);

printf("\n Data entered in the list : \n");

displayList();

return 0;

void createNodeList(int n) {

struct node *fnNode, *tmp;

int num, i;

stnode = (struct node *)malloc(sizeof(struct node));

if(stnode == NULL) {

printf(" Memory can not be allocated.");

} else {

printf(" Input data for node 1 : ");

scanf("%d", &num);

stnode->num = num;

stnode->nextptr = NULL;

tmp = stnode;

for(i = 2; i <= n; i++) {

fnNode = (struct node *)malloc(sizeof(struct node));

if(fnNode == NULL) {

printf(" Memory can not be allocated.");

break;

} else {
 printf(" Input data for node %d : ", i);

scanf(" %d", &num);

fnNode->num = num;

fnNode->nextptr = NULL;

tmp->nextptr = fnNode;

tmp = tmp->nextptr;

void displayList() {

struct node *tmp;

if(stnode == NULL) {

printf(" List is empty.");

} else {

tmp = stnode;

while(tmp != NULL) {

printf(" Data = %d\n", tmp->num);

tmp = tmp->nextptr;

10. Delete a given node from a singly linked list.

#include <malloc.h>

struct node

int value;

struct node *next;

};

typedef struct node snode;

snode *newnode, *ptr;

snode *first = NULL, *last = NULL, *prev = NULL;

snode* create_node(int);

void insert_node(int);

void display();

void delete_node(int);

int main()

int ch=0,n,item;

while (ch!=4)

printf("\n---Linked List Deletion---");

printf("\n1.Create List \n2.Display List \n3.Delete Node \n4.Exit\n");

printf("\nEnter your choice : ");

scanf("%d", &ch);

switch (ch)

case 1:

printf("\nEnter the number of elements : ");

scanf("%d",&n);

insert_node(n);
 break;

case 2:

printf("\nElements in the list are : ");

display();

break;

case 3:

printf("Enter the element to delete : ");

scanf("%d",&item);

delete_node(item);

break;

case 4:

printf("Exiting...");

break;

default:

printf("\nInvalid Choice\n");

break;

return 0;

snode* create_node(int val)

newnode = (snode *)malloc(sizeof(snode));

newnode->value = val;

newnode->next = NULL;

return newnode;

void insert_node(int n)

first = NULL,last=NULL;

int val,i;
 for(i=0;i<n;i++)

printf("\nEnter the value for the Node %d : ",i+1);

scanf("%d", &val);

newnode = create_node(val);

if (first == last && last == NULL)

first = last = newnode;

first->next = NULL;

last->next = NULL;

else

last->next = newnode;

last = newnode;

last->next = NULL;

printf("\nLinked list created\n");

void display()

if (first == NULL)

printf("\nNo nodes in the list to display\n");

else

for (ptr = first;ptr != NULL;ptr = ptr->next)

printf(" %d ", ptr->value);

void delete_node(int item)

int i,pos=0;

struct node *temp,*ptr=first;

if(first==NULL)

printf("nThe List is Empty:n");

else

while(ptr != NULL)

if(ptr->value == item)

break;

pos++;

ptr = ptr->next;

if(pos==0)

ptr=first;

first=first->next ;

printf("The deleted element is:%d",ptr->value);

free(ptr);

else

ptr=first;

for(i=0;i<pos;i++){
 temp=ptr;

ptr=ptr->next ;

temp->next =ptr->next ;

printf("The deleted element is:%d",ptr->value);

free(ptr);

11. Create a doubly linked list of integers and display in forward and backward direction.

#include<stdio.h>

#include<stdlib.h>

struct node

struct node *prev;

struct node *next;

int data;

};

struct node *head;

void insertion(int);

void display_forward();

void display_backward();

int main()

int choice =0,n;

while(choice != 4)

printf("\nDoubly Linked List\n");

printf("\n1.Create List\n2.Display in Forward Order\n3.Display in Backward Order\n4.Exit");

printf("\nEnter your choice : ");

scanf("\n%d",&choice);
 switch(choice)

case 1:

printf("\nEnter the number of elements : ");

scanf("%d",&n);

insertion(n);

break;

case 2:

display_forward();

break;

case 3:

display_backward();

break;

case 4:

exit(0);

break;

default:

printf("Please enter valid choice..");

return 0;

void insertion(int n)

head = NULL;

struct node *ptr,*temp;

int item,i;

for(i=0;i<n;i++)

ptr = (struct node *) malloc(sizeof(struct node));

if(ptr == NULL)
 {

printf("\nOVERFLOW");

else

printf("\nEnter value %d : ",i+1);

scanf("%d",&item);

ptr->data=item;

if(head == NULL)

ptr->next = NULL;

ptr->prev = NULL;

head = ptr;

else

temp = head;

while(temp->next!=NULL)

temp = temp->next;

temp->next = ptr;

ptr ->prev=temp;

ptr->next = NULL;

printf("\nLinked list created\n");

void display_forward()

{
 struct node *ptr;

printf("Elements in the linked list (forward) : ");

ptr = head;

while(ptr != NULL)

printf("%d\t",ptr->data);

ptr=ptr->next;

void display_backward()

struct node *ptr,*last;

printf("Elements in the linked list (backward) : ");

ptr = head;

while(ptr != NULL)

last = ptr;

ptr=ptr->next;

while(last != NULL)

printf("%d\t",last->data);

last=last->prev;

12. Implement Stack using array.

#include<stdio.h>

int stack[100],choice,n,top,x,i;

void push(void);

void pop(void);

void display(void);
int main()

top=-1;

printf("\n Enter the size of STACK[MAX=100]:");

scanf("%d",&n);

printf("\n\t STACK OPERATIONS USING ARRAY");

printf("\n\t--------------------------------");

printf("\n\t 1.PUSH\n\t 2.POP\n\t 3.DISPLAY\n\t 4.EXIT");

do

printf("\n Enter the Choice:");

scanf("%d",&choice);

switch(choice)

case 1:

push();

break;

case 2:

pop();

break;

case 3:

display();

break;

case 4:

{
 printf("\n\t EXIT POINT ");

break;

default:

printf ("\n\t Please Enter a Valid Choice(1/2/3/4)");

while(choice!=4);

return 0;

void push()

if(top>=n-1)

printf("\n\tSTACK is over flow");

else

printf(" Enter a value to be pushed:");

scanf("%d",&x);

top++;

stack[top]=x;

void pop()

if(top<=-1)
 {

printf("\n\t Stack is under flow");

else

printf("\n\t The popped elements is %d",stack[top]);

top--;

void display()

if(top>=0)

printf("\n The elements in STACK \n");

for(i=top; i>=0; i--)

printf("\n%d",stack[i]);

printf("\n Press Next Choice");

else

printf("\n The STACK is empty");

13. Implement Stack using linked list.

#include <stdio.h>

#include <stdlib.h>

void push();

void pop();

void display();

struct node
{

int val;

struct node *next;

};

struct node *head;

void main ()

int choice=0;

printf("\n*********Stack operations using linked list*********\n");

printf("\n----------------------------------------------\n");

while(choice != 4)

printf("\n\nChose one from the below options...\n");

printf("\n1.Push\n2.Pop\n3.Show\n4.Exit");

printf("\n Enter your choice \n");

scanf("%d",&choice);

switch(choice)

case 1:

push();

break;

case 2:

pop();

break;

case 3:

{
 display();

break;

case 4:

printf("Exiting....");

break;

default:

printf("Please Enter valid choice ");

};

void push ()

int val;

struct node *ptr = (struct node*)malloc(sizeof(struct node));

if(ptr == NULL)

printf("not able to push the element");

else

printf("Enter the value");

scanf("%d",&val);

if(head==NULL)

ptr->val = val;

ptr -> next = NULL;

else

ptr->val = val;

ptr->next = head;

head=ptr;

printf("Item pushed");

void pop()

int item;

struct node *ptr;

if (head == NULL)

printf("Underflow");

else

item = head->val;

ptr = head;

head = head->next;

free(ptr);

printf("Item popped");

}
}

void display()

int i;

struct node *ptr;

ptr=head;

if(ptr == NULL)

printf("Stack is empty\n");

else

printf("Printing Stack elements \n");

while(ptr!=NULL)

printf("%d\n",ptr->val);

ptr = ptr->next;

14. Evaluation of postfix expressions.

#include<stdio.h>

int stack[20];

int top = -1;

void push(int x)

stack[++top] = x;

int pop()
{

return stack[top--];

int main()

char exp[20];

char *e;

int n1,n2,n3,num;

printf("Enter the expression :: ");

scanf("%s",exp);

e = exp;

while(*e != '\0')

if(isdigit(*e))

num = *e - 48;

push(num);

else

n1 = pop();

n2 = pop();

switch(*e)

case '+':

n3 = n1 + n2;

break;

case '-':
 {

n3 = n2 - n1;

break;

case '*':

n3 = n1 * n2;

break;

case '/':

n3 = n2 / n1;

break;

push(n3);

e++;

printf("\nThe result of expression %s = %d\n\n",exp,pop());

return 0;

15. Implement Queue using array.

#include<stdio.h>

#include<stdlib.h>

#define maxsize 5

void insert();

void delete();

void display();

int front = -1, rear = -1;

int queue[maxsize];
void main ()

int choice;

while(choice != 4)

printf("\n*************************Main Menu*****************************\n");

printf("\n=================================================================\n");

printf("\n1.insert an element\n2.Delete an element\n3.Display the queue\n4.Exit\n");

printf("\nEnter your choice ?");

scanf("%d",&choice);

switch(choice)

case 1:

insert();

break;

case 2:

delete();

break;

case 3:

display();

break;

case 4:

exit(0);

break;

default:

printf("\nEnter valid choice??\n");

void insert()

{
 int item;

printf("\nEnter the element\n");

scanf("\n%d",&item);

if(rear == maxsize-1)

printf("\nOVERFLOW\n");

return;

if(front == -1 && rear == -1)

front = 0;

rear = 0;

else

rear = rear+1;

queue[rear] = item;

printf("\nValue inserted ");

void delete()

int item;

if (front == -1 || front > rear)

printf("\nUNDERFLOW\n");

return;

else
 {

item = queue[front];

if(front == rear)

front = -1;

rear = -1 ;

else

front = front + 1;

printf("\nvalue deleted ");

void display()

int i;

if(rear == -1)

printf("\nEmpty queue\n");

else

{ printf("\nprinting values .....\n");

for(i=front;i<=rear;i++)

printf("\n%d\n",queue[i]);

}
}

16. Implement Queue using linked list.

#include<stdio.h>

#include<stdlib.h>

struct node

int data;

struct node *next;

};

struct node *front;

struct node *rear;

void insert();

void delete();

void display();

void main ()

int choice;

while(choice != 4)

printf("\n*************************Main Menu*****************************\n");

printf("\n=================================================================\n");

printf("\n1.insert an element\n2.Delete an element\n3.Display the queue\n4.Exit\n");

printf("\nEnter your choice ?");

scanf("%d",& choice);

switch(choice)

case 1:

insert();

break;

case 2:

delete();
 break;

case 3:

display();

break;

case 4:

exit(0);

break;

default:

printf("\nEnter valid choice??\n");

void insert()

struct node *ptr;

int item;

ptr = (struct node *) malloc (sizeof(struct node));

if(ptr == NULL)

printf("\nOVERFLOW\n");

return;

else

printf("\nEnter value?\n");

scanf("%d",&item);

ptr -> data = item;

if(front == NULL)

front = ptr;
 rear = ptr;

front -> next = NULL;

rear -> next = NULL;

else

rear -> next = ptr;

rear = ptr;

rear->next = NULL;

void delete ()

struct node *ptr;

if(front == NULL)

printf("\nUNDERFLOW\n");

return;

else

ptr = front;

front = front -> next;

free(ptr);

void display()

struct node *ptr;

ptr = front;
 if(front == NULL)

printf("\nEmpty queue\n");

else

{ printf("\nprinting values .....\n");

while(ptr != NULL)

printf("\n%d\n",ptr -> data);

ptr = ptr -> next;

17. Traverse a binary search tree in preorder.

#include <stdio.h>

#include <stdlib.h>

struct node {

int element;

struct node* left;

struct node* right;

};

struct node* createNode(int val)

struct node* Node = (struct node*)malloc(sizeof(struct node));

Node->element = val;

Node->left = NULL;

Node->right = NULL;
 return (Node);

void traversePreorder(struct node* root)

if (root == NULL)

return;

printf(" %d ", root->element);

traversePreorder(root->left);

traversePreorder(root->right);

int main()

struct node* root = createNode(40);

root->left = createNode(30);

root->right = createNode(50);

root->left->left = createNode(25);

root->left->right = createNode(35);

root->left->left->left = createNode(15);

root->left->left->right = createNode(28);

root->right->left = createNode(45);

root->right->right = createNode(60);

root->right->right->left = createNode(55);

root->right->right->right = createNode(70);

printf("\n The Preorder traversal of given binary tree is -\n");

traversePreorder(root);

return 0;
}

18. Traverse a binary search tree in inorder.

#include <stdio.h>

#include <stdlib.h>

struct node {

int element;

struct node* left;

struct node* right;

};

struct node* createNode(int val)

struct node* Node = (struct node*)malloc(sizeof(struct node));

Node->element = val;

Node->left = NULL;

Node->right = NULL;

return (Node);

void traverseInorder(struct node* root)

if (root == NULL)

return;

traverseInorder(root->left);

printf(" %d ", root->element);

traverseInorder(root->right);

int main()

struct node* root = createNode(40);

root->left = createNode(30);

root->right = createNode(50);

root->left->left = createNode(25);
 root->left->right = createNode(35);

root->left->left->left = createNode(15);

root->left->left->right = createNode(28);

root->right->left = createNode(45);

root->right->right = createNode(60);

root->right->right->left = createNode(55);

root->right->right->right = createNode(70);

printf("\n The Inorder traversal of given binary tree is -\n");

traverseInorder(root);

return 0;

19. Traverse a binary search tree in postorder.

#include<stdio.h>

#include<stdlib.h>

struct node

int data;

struct node *left, *right;

};

struct node *newNode (int item)

struct node *temporary = (struct node *) malloc (sizeof (struct node));

temporary->data = item;

temporary->left = temporary->right = NULL;

return temporary;

}
void postorder (struct node *root)

if (root != NULL)

postorder (root->left);

postorder (root->right);

printf ("%d ", root->data);

struct node *insert (struct node *node, int data)

if (node == NULL)

return newNode (data);

if (data < node->data)

node->left = insert (node->left, data);

else if (data > node->data)

node->right = insert (node->right, data);

return node;

int main ()

struct node *root = NULL;

insert (root, 7);

insert (root, 5);

insert (root, 8);

insert (root, 14);

insert (root, 11);

insert (root, 16);

printf ("The postorder is :\n");

postorder (root);

return 0;

20. Implement exchange sort.

#include<stdio.h>

main()

float arr[100],temp;

int i,j,elements;

printf("Enter the number of elements in the array: ");

scanf("%d",&elements);

for(i = 0; i < elements; i++)

printf("Arr[%d}=",i);

scanf("%f",&arr[i]);

printf("\nExisting list\n");

for(i = 0; i < elements; i++)

printf("arr[%d]=%g\n",i,arr[i]);

for(i = 0; i < elements-1; i++)

if(arr[j]>arr[j+1])

temp=arr[j];

arr[j]=arr[j+1];

arr[j+1]=temp;

printf("\nSorted List\n");

for(i = 0; i < elements; i++)

printf("arr[%d]=%g\n",i,arr[i]);

getch();

21. Implement selection sort.

#include<stdio.h>

main()

float arr[100],temp;

int i,j,elements,min;

printf("Enter the number of elements in the array: ");

scanf("%d",&elements);

for(i = 0; i < elements; i++)

printf("Arr[%d}=",i);

scanf("%f",&arr[i]);

printf("\nExisting list\n");

for(i = 0; i < elements; i++)

printf("arr[%d]=%g\n",i,arr[i]);

for(i = 0; i < elements-1; i++)

{
 min=i;

for(j=i+1;j<elements;j++)

if(arr[j]<arr[min])

min=j;

temp=arr[i];

arr[i]=arr[min];

arr[min]=temp;

printf("\nSorted List\n");

for(i = 0; i < elements; i++)

printf("arr[%d]=%g\n",i,arr[i]);

getch();

22. Implement insertion sort.

#include<stdio.h>

main()

float arr[100],temp;

int i,j,elements;

printf("Enter the number of elements in the array: ");

scanf("%d",&elements);

for(i = 0; i < elements; i++)

printf("Arr[%d}=",i);

scanf("%f",&arr[i]);

printf("\nExisting list\n");

for(i = 0; i < elements; i++)

printf("arr[%d]=%g\n",i,arr[i]);

for(i = 1; i < elements; i++)

temp=arr[i];

for(j=i-1;((j>=0)&&(arr[j]>temp));j--)

{arr[j+1]=arr[j];

arr[j+1]=temp;

printf("\nThe Sorted List\n");

for(i=0;i<elements;i++)

printf("arr[%d]=%g\n",i,arr[i]);

getch();

23. Implement quick sort.

#include<stdio.h>

main()

void q_sort(float [],int,int);

float arr[100];

int i,elements;

printf("Enter the number of elements in the array: ");

scanf("%d",&elements);

for(i = 0; i < elements; i++)

printf("Arr[%d}=",i);

scanf("%f",&arr[i]);

printf("\nExisting list\n");

for(i = 0; i < elements; i++)

printf("arr[%d]=%g\n",i,arr[i]);

q_sort(arr,0,elements-1);
printf("\nThe Sorted List\n");

for(i=0;i<elements;i++)

printf("arr[%d]=%g\n",i,arr[i]);

getch();

void q_sort(float a[],int lower,int upper)

int split(float a[],int,int);

int v;

if(upper>lower)

v=split(a,lower,upper);

q_sort(a,lower,v-1);

q_sort(a,v+1,upper);

int split(float a[],int lr,int ur)

int v,p,q,t;

p=lr+1;

q=ur;

v=a[lr];

while(q>=p)

while(a[p]<v)p++;

while(a[q]>v)q--;

if(q>p)

t=a[p];a[p]=a[q];a[q]=t;

}
 t=a[lr];

a[lr]=a[q];

a[q]=t;

return q;