Implementation of Simple Queue in c

#include<stdio.h>

#include<conio.h>

#include<string.h>

#define size 5

int f=-1,r=-1,a[5];

void enqueue(int);

int dequeue(void);

void main()

{

 int i,j,k,l,m,n;

 clrscr();

 enqueue(10);

 enqueue(20);

 enqueue(30);

 enqueue(40);

 enqueue(50);

            i=dequeue();

printf("\nDequeued value is %d",i);

            j=dequeue();

printf("\nDequeued value is %d",j);

            k=dequeue();

printf("\nDequeued value is %d",k);

            enqueue(60);

            l=dequeue();

printf("\nDequeued value is %d",l);

getch();

}

void enqueue(int y)

{

            if(r==size)

            {

                        printf("\nQueue is overflow");

            }

            else if(f==-1 && r==-1)

            {

                        f=0;r=0;

                        a[r]=y;

                        printf("\nValue enqueued is %d",a[r++]);

            }

            else

            {

                        a[r]=y;

                        printf("\nValue Enqueued is %d",a[r++]);

            }

}

int dequeue()

{

            if(f==r)

            {

                        f=-1;r=-1;

                        printf("\nQueue is underflow");

                        return 0;

            }

            else

            {

                        return a[f++];

            }

}

Implementation of Circular Queue in c

Implementation of Circular Queue in c

#include<stdio.h>

#include<conio.h>

#include<string.h>

#define size 5

int f=-1,r=-1,a[5];

void enqueue(int);

int dequeue(void);

void main()

{

 clrscr();

 enqueue(10);

 enqueue(20);

 enqueue(30);

 enqueue(40);

 enqueue(50);

dequeue();

dequeue();

 enqueue(60);

 enqueue(70);

getch();

}

void enqueue(int y)

{

            if(f==0 && r==size)

            {

                        printf("\nQueue is full");

            }

            else if(f!=0 && r==size)

            {

                        r=0;

                        a[r]=y;

                        printf("\nValue enqueued is %d at a[%d]",a[r++],r);

            }

            else if(f==-1 && r==-1)          

            {                         

                        f=0;r=0;                   

                        a[r]=y;

                        printf("\nValue enqueued is %d at a[%d]",a[r++],r);

            }

            else if(f==r)

            {

                        printf("\nQueue is full");

            }

            else

            {

                        a[r]=y;

                        printf("\nValue enqueued is %d at a[%d]",a[r++],r);

            }

}

int dequeue()

{

            if(f==r)

            {

                        f=-1;r=-1;

                        printf("\nQueue is underflow");

                        return 0;

            }

            else

            {

                        printf("\nDequeued value is %d at a[%d]",a[f],f);

                        return a[f++];              

            }                                 

}                          

Stack program in c with pop(), push() and display() functions

Stack program in c with pop(), push() and display() function.

#include<stdio.h>

#include<conio.h>

#include<string.h>

#define max 5

int top=-1;

void push();

int pop();

void display();

int stack_arr[max];

void main()

{

int choice;

clrscr();

while(1)

{

printf("1.Push\n");

printf("2.Pop\n");

printf("3.Display\n");

printf("4.Quit\n");

printf("Enter your choice\n");

scanf("%d",&choice);

switch(choice)

{

case 1:

push();

break;

case 2:

pop();

break;

case 3:

display();

break;

case 4:

return 0;

default:

printf("Wrong choice\n");

}

}

}

void push()

{

int pushed_item;

if(top==(max-1))

{

printf("Stack is overflow\n");

}

else

{

printf("Enter the item to pushed on stack\n");

scanf("%d",&pushed_item);

top=top+1;

stack_arr[top]=pushed_item;

}

}

int pop()

{

int e;

if(top==-1)

printf("Stack underflow\n");

else

{

e=stack_arr[top];

printf("popped element is %d\n",e);

top=top-1;

}

return(e);

}

void display()

{

int i;

if(top==-1)

printf("Stack is empty\n");

else

{

printf("Stack elements\n");

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

{

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

}

}

}

This Program is for serial port


#include<stdio.h>
#include<conio.h>
#define base 0x3f8

void main()
{
char ch,ch1;
clrscr();

       //printf("\n enter data");
while(ch!='$')
{
//printf("\n");
scanf("%c",&ch);
outportb (base+1,0x00);
outportb (base+3,0x80);
outportb (base,0x30);
outportb (base+1,0x00);
outportb(base+3,0x03);
outportb (base+4,0x03);
outportb(base, ch);
ch1=inportb(base);
printf("%c",ch);

}

getch();
}


This program will continue running until you have given "$" sign as input.