FCFS and SJF program

 This is a program for the implementation of First Come First Serve and Shortest Job First Scheduling. If you have any doubts, please let me know.

#include<stdio.h>

#include<string.h>

struct process

{

   int arr,bur,wait,turn,t;

   char pid[5];

}p[100],temp;

int n;

void chart()

{

            int i,j,k;

            printf("0");

            for(j=0;j<n;j++)

            {

                        i=0;

                        while(i!=p[j].bur)

                        {

                                    printf("=");

                                    i++;

                        }

            printf("%d",p[j].t);

            }

            printf("\n");

            i=0;

            printf("p%s",p[0].pid);

           

            for(j=0,k=1;j<n-1;j++,k++)

            {

                        while(i!=p[j].t)

                        {

                                    printf(" ");

                                    i++;

                        }

            printf("p%s",p[k].pid);

            }

            printf("\n");

}

void avg()

    {

        int i;

        float avgw=0,avgt=0;

        for(i=0;i<n;i++)

       {

        avgw=avgw+p[i].wait;

        avgt=avgt+p[i].turn;

      }

    avgw=avgw/n;

    avgt=avgt/n;

    printf("\nAverage waiting time :%d\nAverage turnaround time :%d\n",avgw,avgt);

 }

void disp()

{

         printf("\npid\tburst\tarrival\twait\tturnaround\n");

         int i;

         for(i=0;i<n;i++)

            {

            printf("%s\t%d\t%d\t%d\t%d\n",p[i].pid,p[i].bur,p[i].

arr,p[i].wait,p[i].turn);

        }

    avg();

    chart();

}

void fcfs()

{

        int i,j;

         for(i=0;i<n-1;i++)

            {

            for(j=i+1;j<n;j++)

               {

                if(p[i].arr>p[j].arr)

                {

                    temp=p[i];

                    p[i]=p[j];

                    p[j]=temp;

                }

             }

        }

        p[0].wait=0;

        p[0].turn=p[0].wait+p[0].bur;

                        p[0].t=p[0].bur;

        for(i=1;i<n;i++)

       {

            p[i].t=p[i-1].t+p[i].bur;

            p[i].wait=p[i-1].t-p[i].arr;

            p[i].turn=p[i].wait+p[i].bur;

      }

                        disp();

}

void sjf()

{

            int i,j;

            for(i=0;i<n-1;i++)

            {

            for(j=i+1;j<n;j++)

                {

                if(p[i].arr>p[j].arr)

                {

                    temp=p[i];

                    p[i]=p[j];

                    p[j]=temp;

                }

                }

            }

            for(i=1;i<n-1;i++)

            {

            for(j=i+1;j<n;j++)

                {

                if(p[i].bur>p[j].bur)

                {

                    temp=p[i];

                    p[i]=p[j];

                    p[j]=temp;

                }

                }

          }

            p[0].wait=0;

            p[0].turn=p[0].wait+p[0].bur;

            p[0].t=p[0].bur;

            for(i=1;i<n;i++)

            {

               p[i].t=p[i-1].t+p[i].bur;

               p[i].wait=p[i-1].t-p[i].arr;

               p[i].turn=p[i].wait+p[i].bur;

            }

                disp();

}

void main()

{

    int j,i,ch;

    printf("Enter number of processess : ");

    scanf("%d",&n);

    for(i=0;i<n;i++)

        {

            printf("Enter pid : ");

            scanf("%s",p[i].pid);

            printf("enter arrival time : ");

            scanf("%d",&p[i].arr);

            printf("Enter burst time : ");

            scanf("%d",&p[i].bur);

        }

    printf("\nMENU\n1.FCFS\n2.SJF\n3.exit\nEnter your choice : ");

    scanf("%d",&j);

    switch(j)

    {

    case 1:fcfs();

              break;

    case 2:  sjf();

              break;

    case 3:

          break;

    default : printf("Wrong Choice");

    }

}

Program for Best Fit, Worst Fit and First Fit

This is a program for the implementation of Best fit, Worst Fit, and First Fit for the operating systems lab. If you have any doubts please let me know.

#include<stdio.h>

#include<stdlib.h>

int i,j,n,x,ch,size,ch1,ch2,y,pid;

struct alloc1

{

  int id,sa,ea,size;

  struct alloc1 *next;

}*start=NULL,*ptr=NULL,*newn=NULL;

struct free1

{

  int stadd,eadd,size1;

  struct free1 *next;

}*start1=NULL,*newn1=NULL,*ptr2=NULL,*preptr2=NULL;

void displayfree(struct free1 *temp)

{

printf("\n\nFree Space\n");

temp=start1;

while(temp!=NULL)

    {

    printf("%d",temp->stadd);

    printf(" - %d\n",temp->eadd);

    temp=temp->next;

    }}

void display(struct alloc1 *temp1)

{

printf("\n\nAllocated\n");

temp1=start;

while(temp1!=NULL)

    {

                        printf("p%d\t",temp1->id);

    printf("%d",temp1->sa);

    printf(" - %d\n",temp1->ea);

    temp1=temp1->next;

    }

}

void init()

{

   newn->sa=ptr2->stadd;

   newn->ea=newn->sa+size-1;

   ptr2->stadd=ptr2->stadd+size;

   ptr2->size1=ptr2->size1-size;

}

void main()

{

    printf("\nEnter the number of processes:\n");

  scanf("%d",&n);

   for(i=0;i<n;i++)

  {

         newn=(struct alloc1 *) malloc(sizeof(struct alloc1));

         printf("\nEnter process id: ");

         scanf("%d",&newn->id);

         printf("\nEnter the start address: ");

         scanf("%d",&newn->sa);

         printf("\nEnter the end address: ");

         scanf("%d",&newn->ea);

         newn->size=(newn->ea-newn->sa)+1;

         if(start==NULL)

        {

            start=newn;

            start->next=NULL;

            ptr=start;

        }

       else

       {

            while(ptr->next!=NULL)

            {

            ptr=ptr->next;

            }

            ptr->next=newn;

            ptr=ptr->next;

            ptr->next=NULL;

       }

}

 printf("\nEnter the details of free space\n");

 do

 {

    newn1=(struct free1 *) malloc(sizeof(struct free1));

   printf("\nEnter the starting address: ");

   scanf("%d",&newn1->stadd);

   printf("\nEnter the ending address: ");

   scanf("%d",&newn1->eadd);

   newn1->size1=(newn1->eadd-newn1->stadd)+1;

    if(start1==NULL)

  {

    start1=newn1;

    start1->next=NULL;

  ptr2=start1;

   }

   else

   {

     while(ptr2->next!=NULL)

       ptr2=ptr2->next;

     ptr2->next=newn1;

     ptr2=ptr2->next;

     ptr2->next=NULL;

  }

  ptr2=start1;

  printf("\nPress 1 to add more...");

  scanf("%d",&ch);

 }while(ch==1);

printf("\n BEFORE FITTING\n");

displayfree(ptr2);

 ptr=start;

display(ptr);

do

{

  printf("\nEnter the size of new process: ");

  scanf("%d",&size);

  printf("\nEnter the process id:");

  scanf("%d",&pid);

 newn=((struct alloc1 *)malloc(sizeof(struct alloc1)));

   newn->next=NULL;  

   newn->size=size;

               newn->id=pid;

     printf("\nMENU:\n1.First fit\n2.Best fit\n3.Worst fit\n4.Exit\n");

     printf("\nEnter your choice:\n");

     scanf("%d",&ch1);

     switch(ch1)

     {

       case 1:

   ptr2=start1;

   if(ptr2->size1==size)

   {

   start1=ptr2->next;

   }

   else

   {

   while(ptr2->size1<size)

   {

    if(ptr2->next==NULL)

     {

        printf("\nInsufficient memory");

  goto lab;

      }

   preptr2=ptr2;

   ptr2=ptr2->next;

   if(ptr->size==size)

   {

   preptr2->next=ptr2->next;

   }}}

   init(); ptr=start;

while(ptr->next!=NULL)

   ptr=ptr->next;

      ptr->next=newn;

   printf("\nFIRST FIT\n");

   display(ptr);

   displayfree(ptr2);

          lab: break;

case 2:

   ptr2=start1;

   x=1000;

   while(ptr2!=NULL)

   {

   if((ptr2->size1>=size)&&(ptr2->size1<=x))

   {

   x=ptr2->size1;

   }

   ptr2=ptr2->next;

  }

  if(x==1000)

  {

   printf("\nInsufficient memory");

  break;

  }

   ptr2=start1;

   while(ptr2->size1!=x)

   {

   preptr2=ptr2;

   ptr2=ptr2->next;

   }

init();

if(x==size)

   preptr2->next=ptr2->next;

   ptr=start;

   while(ptr->next!=NULL)

   ptr=ptr->next;

   ptr->next=newn;

   printf("\nBEST FIT\n");

   display(ptr);

   displayfree(ptr2);

break;

case 3:   

   ptr2=start1;

       y=0;

   while(ptr2!=NULL)

   {

   if((ptr2->size1>=size)&&(ptr2->size1>=y))

   {

   y=ptr2->size1;

   }

   ptr2=ptr2->next;

  }

if(y==0)

   {

   printf("\nInsufficient memory");

  break;

   }

   ptr2=start1;

   while(ptr2->size1!=y)

   {

   preptr2=ptr2;

   ptr2=ptr2->next;

   }

   if(y==size)

   {

   preptr2->next=ptr2->next;

   }

   init(); ptr=start;

   while(ptr->next!=NULL)

   {

   ptr=ptr->next;

   }

   ptr->next=newn;

  printf("\nWORST FIT\n");

   display(ptr);

   displayfree(ptr2);

   break;

case 4:break;

default:break;

}

printf("\npress 1 to add more..");

scanf("%d",&ch2);

}while(ch2==1);

}