Evaluation of Post-fix Expression

ADT Stack implementation and use  it for evaluation of Post-fix Expression

/*Progam for Postfix Evalution */
#define SIZE 50            /* Size of Stack */
#include <ctype.h>
#include<stdio.h>
int s[SIZE];
int top=-1;       /* Global declarations */

push(int elem)
{                       /* Function for PUSH operation */
 s[++top]=elem;
}

int pop()
{                      /* Function for POP operation */
 return(s[top--]);
}

main()
{                         /* Main Program */
 char pofx[50],ch;
 int i=0,op1,op2;
 printf("\n\nRead the Postfix Expression ? ");
 scanf("%s",pofx);
 while( (ch=pofx[i++]) != '\0')
 {
  if(isdigit(ch))
push(ch-'0'); /* Push the operand */
  else
  {        /* Operator,pop two  operands */
op2=pop();
op1=pop();
switch(ch)
   {
case '+':push(op1+op2);break;
case '-':push(op1-op2);break;
   case '*':push(op1*op2);break;
   case '/':push(op1/op2);break;
   }
  }
 }
 printf("\n Given Postfix Expn: %s\n",pofx);
 printf("\n Result after Evaluation: %d\n",s[top]);
}

Merge Sort Program

Merge Sort Program

#include<stdio.h>
#define MAX 50

void mergeSort(int arr[],int low,int mid,int high);
void partition(int arr[],int low,int high);

int main(){

int merge[MAX],i,n;

printf("Enter the total number of elements: ");
scanf("%d",&n);

printf("Enter the elements which to be sort: ");
for(i=0;i<n;i++){
scanf("%d",&merge[i]);
}

partition(merge,0,n-1);

printf("After merge sorting elements are: ");
for(i=0;i<n;i++){
printf("%d ",merge[i]);
}

return 0;
}

void partition(int arr[],int low,int high){

int mid;

if(low<high){
mid=(low+high)/2;
partition(arr,low,mid);
partition(arr,mid+1,high);
mergeSort(arr,low,mid,high);
}
}

void mergeSort(int arr[],int low,int mid,int high){

int i,m,k,l,temp[MAX];

l=low;
i=low;
m=mid+1;

while((l<=mid)&&(m<=high)){

if(arr[l]<=arr[m]){
temp[i]=arr[l];
l++;
}
else{
temp[i]=arr[m];
m++;
}
         i++;
}

if(l>mid){
         for(k=m;k<=high;k++){
temp[i]=arr[k];
             i++;
}
    }
else{
         for(k=l;k<=mid;k++){
temp[i]=arr[k];
             i++;
}
    }

    for(k=low;k<=high;k++){
arr[k]=temp[k];
    }
}

Quick Sort Program

Quick Sort Program 

 #include<stdio.h>

void quicksort(int [10],int,int);

int main(){
  int x[20],size,i;

  printf("Enter size of the array: ");
  scanf("%d",&size);

  printf("Enter %d elements: ",size);
  for(i=0;i<size;i++)
scanf("%d",&x[i]);

  quicksort(x,0,size-1);

  printf("Sorted elements: ");
  for(i=0;i<size;i++)
printf(" %d",x[i]);

  return 0;
}

void quicksort(int x[10],int first,int last){
int pivot,j,temp,i;

 if(first<last){
pivot=first;
i=first;
j=last;

while(i<j){
while(x[i]<=x[pivot]&&i<last)
 i++;
while(x[j]>x[pivot])
 j--;
if(i<j){
 temp=x[i];
x[i]=x[j];
x[j]=temp;
}
}

temp=x[pivot];
x[pivot]=x[j];
x[j]=temp;
quicksort(x,first,j-1);
quicksort(x,j+1,last);

}
}

Circular Queue Using Double linked list

Circular Queue Using Double linked list

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>

struct node
{
int data;
struct node *next;
struct node *prev;
};

struct node *head=NULL,*temp;

void insert(int ele)
{
struct node *tempe;
temp=(struct node *)malloc(sizeof(struct node));
temp->data=ele;
temp->next=NULL;
if(head==NULL)
{
head=temp;
temp->next=head;
}
else
{
tempe=head;
while(tempe->next!=head)
{
tempe=tempe->next;
}
tempe->next=temp;
temp->next=head;
      temp->prev=tempe;
}
}

void display()
{
struct node *temp1;
temp1=head;
while(temp1->next!=head)
{
printf("%d\t",temp1->data);
temp1=temp1->next;
}
printf("%d",temp1->data);
}


void del(int pos)
{
struct node *temp1,*temp2;

if(head==NULL)
{
printf("Circular Queue is Emplty");
}
else if(pos==1)
{
temp1=head;
temp2=head;
while(temp1->next!=head)
{
temp1=temp1->next;
}
head=head->next;
temp1->next=head;
free(temp2);
}
else
{
temp2=head;
while(--pos!=0)
{
temp1=temp2;
temp2=temp2->next;

}
temp1->next=temp2->next;
free(temp2);
}
}
  void main()
{
int n,e,ch;
head=NULL;
while(1)
{
printf("\n1.Insert\n2.Delete\n3.Display\n4.Exit");
printf("\nEnter your Choice : ");
scanf("%d",&ch);
switch(ch)
{
case 1: printf("\nEnter the Number : ");
scanf("%d",&n);
insert(n);break;
case 2: printf("\nEnter the Position for Deleting : ");
scanf("%d",&e);
del(e);  break;
case 3:
display();  break;
case 4: exit(0);   break;
default: printf("\nYour Choice is Wrong");
}
}

}

Queue Operations using Single Linked List

Queue Operations using Single Linked List

#include<stdio.h>
#include<conio.h>
#include <stdlib.h>    

struct node
{
int data;
struct node *next;
};
struct node *front=NULL,*rear=NULL;

void insert()
{
int item;
struct node *temp,*tempe;

printf("\nEnter the Number : ");
scanf("%d",&item);
temp=(struct node *) malloc(sizeof(struct node));

temp->data=item;
temp->next=NULL;

if(rear==NULL)
{
front=temp;
rear=temp;
}
else
{
rear->next=temp;
rear=temp;
}
}



void del()
{


if(front==NULL)
printf("\Queue is Empty ");
else if(rear==front)
front=rear=NULL;
else
{
printf("%d is Deleted ",front->data);
front=front->next;
}
}

void display()
{
struct node *temp;

if(front==NULL && rear==NULL)
printf("\nQueue is Empty");
else
{
temp=front;
printf("\n Elements are : ");
while(temp->next!=NULL)
{
printf("%d\t",temp->data);
temp=temp->next;
}
printf("%d",temp->data);
}
}

void main()
{
int ch;
while(1)
{
printf("\n1.Insert\n2.Delete\n3.Display\n4.Exit");
printf("\nEnter your Choice : ");
scanf("%d",&ch);
switch(ch)
{
case 1:  insert();break;
case 2:  del();break;
case 3:  display();break;
case 4: exit(0);break;
            default: printf("\nYour Choice is Woring");
}
}

}