OS BANKERS ALGORITHM PROGRAM

#include<stdio.h>
#include<string.h>
void main()
{
int max[10][10],need[10][10],alloc[10][10],finish[10]={0},avail[10],work[10];
int i,j,count=0,t,p,r;
printf("Enter the no of processes:\n");
scanf("%d",&p);
printf("Enter the no of resources:\n");
scanf("%d",&r);
printf("Enter the max for each process:");
for(i=0;i<p;i++)
{
printf("\nFor process %d",i);
for(j=0;j<r;j++)
{
scanf("%d",&max[i][j]);
}
}
printf("Enter the allocation for each process:\n");
for(i=0;i<p;i++)
{
printf("\nFor process %d",i);
for(j=0;j<r;j++)
{
scanf("%d",&alloc[i][j]);
}
}
printf("Enter availability of each resource:");
for(j=0;j<r;j++)
scanf("%d",&avail[j]);
do{
for(j=0;j<r;j++)
work[j]=avail[j];

for(i=0;i<p;i++)
{
for(j=0;j<r;j++)
{
need[i][j]=max[i][j]-alloc[i][j];

}
}
count=0;
while(count<8)
{

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

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

if(finish[i]==0 && need[i][j]<=work[j])
;
else
break;
}
if(j>=r)
{

for(t=0;t<r;t++)
{
work[t]+=max[i][t];
}
finish[i]=1;
printf("\t%d",i);
}
}
count++;
}
for(i=0;i<p;i++)
if(finish[i]!=1)
break;
if(i==p)
printf("\nsystem is in safe state");
else
printf("\nunsafe state");
for(i=0;i<p;i++)
finish[i]=0;
printf("\nAre there any extra resource requests?.....");
scanf("%d",&i);
if(i)
{
printf("\nBy which process...");
scanf("%d",&t);
printf("\nEnter request...");
for(j=0;j<r;j++)
{
scanf("%d",&i);
alloc[t][j]+=i;
avail[j]-=i;
}
}
else
break;
}while(1);
}

 

OS PRODUCER CONSUMER PROBLEM USING SEMAPHORES

#include<stdio.h>

#define BUFFER_SIZE 3

int buffer[BUFFER_SIZE],item;

int fillCount = 0; // items produced

int emptyCount = BUFFER_SIZE; // remaining space

producer() {

    while (1) {

        item = produceItem();

      if(item==0)

      return;

      if(emptyCount==0)

      {printf("\nbuffer full");

      break;

      }

        emptyCount--;

           buffer[emptyCount]=item;

      printf("\n %d put into the buffer..",item);

        fillCount++;

     

    }

}

consumer() {

    while (1) {

      if(fillCount==0)

      {printf("\nbuffer empty");

      break;

      }

        fillCount--;

      item=buffer[emptyCount];

            printf("\n %d removed from buffer..",item);

        emptyCount++;

        printf("\n %d consumed..",item);

     

    }

}

int produceItem()

{

int n;

printf("\n Enter the number for production (0 to stop)..\n");

scanf("%d",&n);

return n;

}

int main()

{

char i;

while(i!='y' && i!='Y')

{

producer();

consumer();

printf("\nDo you want to exit...(Y or N)....");

scanf("%c",&i);

}

return 1;

}

OS SJF AND FCFS SCHEDULING PROGRAMS

#include<stdio.h>

int main()

{

int p[10],bt[10],wt[10],n,key,tmp,i,j;

floatawt=0.0,awt2=0.0;

printf("Enter the no. of processes: ");

scanf("%d",&n);

printf("Enter the burst times\n");

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

{

p[i]= i+1;

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

}

wt[0]=0,tmp=0;

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

{

awt += tmp;

tmp += bt[i];

wt[i+1]= tmp;

printf("\nWaiting time of process %d is %d \n turn around time= %d ",i,wt[i],wt[i+1]);

}

awt/=n;

printf("Average waiting time for FCFS = %.3f\n",awt);

tmp=0;

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

{key=bt[i];

tmp=p[i];

for(j=i-1;j>=0 &&bt[j]>key ; j--)

{

bt[j+1]=bt[j];

p[j+1]=p[j];

}

bt[j+1]=key;

p[j+1]=tmp;

}

tmp=0,wt[0]=0;

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

{

awt2 += tmp;

tmp += bt[i];

wt[i+1]= tmp;

printf("\nWaiting time of process %d is %d \n turn around time= %d ",i,wt[i],wt[i+1]);

}

awt2 /= n;

printf("Average waiting time for SJF= %.3f\n",awt2);

if(awt<awt2)

printf("For the given processes, FCFS is better than SJF since %f<%f", awt,awt2);

else

printf("For the given processes, SJF is better than FCFS since %f>%f", awt,awt2);

return 0;

}

FS BTREES

#include <iostream>
#include <cmath>

using namespace std;

struct node
{
int ele[4];
int child[4];
};

class btree
{
public:
node *tree[10][10];
int count[10];
int leaf;
int path[10];

btree();
node* create_node();
void insert(int);
void main_search(int);
void display_tree();
void insert_node(node*,int);
void search(int);
int search_node (node*,int);
int nodefull(node*);
void split(node*);
};

btree::btree()
{
leaf=-1;
for (int i=0;i<10;i++)
{count[i]=-1;path[i]=-1;}
}

node* btree::create_node()
{
node *n;
n = new node;
for (int i=0;i<4;i++) {n->ele[i]=-1;n->child[i]=-1;}
return n;
}


void btree::insert(int key)
{
int n, parent;
node *first_node;
if (leaf==-1)
{
first_node=create_node();
tree[0][0]=first_node;
leaf++;count[0]++;
first_node->ele[0]=key;       
}
else if (leaf==0)
{
if (nodefull(tree[0][0])) {path[leaf]=0;split(tree[0][0]);insert(key);}
else insert_node(tree[0][0],key);
}   
else{
search(key);
n=path[leaf];
parent=path[leaf-1];

if ( (nodefull(tree[leaf][n])) )
{
split(tree[leaf][n]);
insert(key);
}
else
insert_node(tree[leaf][n],key);
}
}

void btree::main_search(int key)
{
int flag=0, i;   
node *node1;
search(key);
node1=tree[leaf][path[leaf]];

for (i=0;node1->ele[i]!=-1;i++)
if (node1->ele[i]==key) {flag=1; break;}

cout<<"\nThe path traversed is: ";
for (i=0;path[i]!=-1;i++)
cout<<path[i]<<" -> ";

if (flag) cout <<"\nElement Found";
else cout<<"\nNot Found";
}

void btree::display_tree()
{
int i,j,k;   
for (i=0;i<=leaf;i++)
{
cout<<"\n\nLevel------ " <<i<<"\n";
for (j=0;j<=count[i];j++)
{
for (k=0;tree[i][j]->ele[k]!=-1;k++)
cout<<" "<<tree[i][j]->ele[k];
cout<<"\t";
}
}
}

void btree::search(int key)
{
int i,j,temp;   
path[0]=0;                //always start the path from root
if (leaf){                // search only if there are more than 1 level
j=0;       
for (i=0;i<leaf;i++)
{
temp=search_node(tree[i][j],key);
path[i+1]=temp;
j=temp;
}}
}   

int btree::search_node(node *node1, int key)
{
for (int i=0;i<4;i++)
{
if (key<=node1->ele[i]) return node1->child[i];
else if (node1->ele[i+1]==-1) return node1->child[i];
}
}

int btree::nodefull(node *node1)
{
if (node1->ele[3]!=-1) return 1;
else return 0;
}

void btree::insert_node(node *node1, int key)
{
int flag=0, count=-1,i,j, x, y, l,t;
node *newnode, *n1;
for (i=0;i<4;i++) if (node1->ele[i]!=-1) ++count;
i=0;
while (!flag && node1->ele[i]!=-1)
{
if (node1->ele[i] > key)            //not considering duplicate entries
{
flag=1;           
for (int j=count;j>=i;j--)
node1->ele[j+1]=node1->ele[j];
node1->ele[i]=key;
}
i++;
}
if (!flag)                        //highest element added at end
{
node1->ele[count+1]=key;   
for (i=leaf-1;i>=0;i--)
{
n1=tree[i][path[i]];           
for (t=0;n1->ele[t]!=-1;t++);
n1->ele[t-1]=key;
}    }

for (i=0;i<=count+1;i++)
cout<<"\t\t"<<node1->ele[i];
}


void btree::split(node *oldnode)
{
node *newnode, *parent, *n1, *n2;
int i,j,k,n,t,x,y,pos;
newnode = create_node();

newnode->ele[0]=oldnode->ele[2];        //copy elements to new node
newnode->ele[1]=oldnode->ele[3];


oldnode->ele[2]=-1;                //delete entries in old node
oldnode->ele[3]=-1;


t=count[leaf];
n=path[leaf];
for (i=t,j=t+1;i>n;i--,j--)            //move the elements in leaf level one place right
tree[leaf][j]=tree[leaf][i];   



tree[leaf][n+1] = newnode;            //insert new node to the tree
count[leaf]++;

x=leaf;

if (count[leaf]+1==1) t=1; else t=log(count[leaf]+1)/log(2);    //how many levels does the tree need?               

if (t!=leaf)                        //increase the level of the tree
{
++leaf;
count[leaf]=count[x];
   
for (i=0;i<=count[leaf];i++)            //copy the leaf nodes to the new level
std::swap(tree[leaf][i],tree[x][i]);
}

for (i=leaf-1;i>=0;i--) count[i]=-1;        //make the tree empty

for (i=t,j=i-1;i>0;i--,j--)
{
for (k=0;k<(count[i]+1)/2;k++)
{
n1=tree[i][2*k];
n2=tree[i][(2*k)+1];           

for (x=0;n1->ele[x]!=-1;x++);    //find last element in the nodes
for (y=0;n2->ele[y]!=-1;y++);

newnode=create_node();
count[j]++;
tree[j][count[j]]=newnode;

newnode->ele[0]=n1->ele[x-1];
newnode->child[0]=2*k;
newnode->ele[1]=n2->ele[y-1];
newnode->child[1]=(2*k)+1;
}


if (count[i]!=1 && count[i]%2==0)            //one node is remaining
{
n2=tree[i][count[i]];   
for (y=0;n2->ele[y]!=-1;y++);       
newnode->ele[2]=n2->ele[y-1];
newnode->child[2]=count[i];
}
}
}


int main()
{
btree bt;
int choice, key;

while(1)
{
cout<<"\n\n\nMain Menu\n-------------------\n1.Insert\n2.Search\n3.Display Tree\n4.Exit\n\nEnter your choice:";
cin>>choice;
switch(choice)
{
case 1:    cout<<"\nEnter the element:";
    cin>>key;
    bt.insert(key);
    break;
case 2:cout<<"Enter the key:";
    cin>>key;
    bt.main_search(key);
    break;
case 3: bt.display_tree();
    break;
case 4: return 0;
default: cout<<"\nEnter valid choice";
}
}
}

Fs cosequential processing

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
class coseq
{
public:   
string list1[100], list2[100];
int count1, count2;

void load_list();
void sort_list();
void match();
};

void coseq::load_list()
{
fstream file;
string name;
count1=-1;count2=-1;
file.open("name1.txt");
while (!file.eof()){
name.erase();       
getline(file,name);       
list1[++count1]=name;
}
file.close();
file.open("name2.txt");
while (!file.eof()){
name.erase();       
getline(file,name);       
list2[++count2]=name;
}
file.close();
}

void coseq::sort_list()
{
int i,j;
string temp;   
for (i=0;i<=count1;i++)
{
for (j=i+1;j<=count1;j++)
{
if (list1[i]>list1[j])
{
  temp=list1[i];
  list1[i]=list1[j];
  list1[j]=temp;
}}}


for (i=0;i<=count2;i++)
{
for (j=i+1;j<=count2;j++)
{
if (list2[i]>list2[j])
{
temp=list2[i];
list2[i]=list2[j];
list2[j]=temp;
}}}
}

void coseq::match()
{
int i=0,j=0;
while (i<=count1 && j<=count2)
{
if (list1[i]==list2[j]) {cout<<"\n"<<list1[i];i++;j++;}
if (list1[i] < list2[j]) i++;
if (list1[i] > list2[j]) j++;
}
}
   
   
int main()
{
coseq c1;
c1.load_list();
c1.sort_list();
c1.match();   
return 0;
}   

Fs lab program for variable lenght record using RRN

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
using namespace std;
class student
{
  public:
      string USN;
      string Name;
      string Branch;
      int Semester;
      string buffer;
      int count;

      int rrn_list[100];

      void read_data();
      void pack();
      void write_to_file();
      void unpack();
      void create_rrn();
      void search_by_rrn(int);     
};
void student::read_data()
{
      cout<<"\nUsn:";
      cin>>USN;
      cout<<"\nName:";
      cin>>Name;
      cout<<"\nBranch:";
      cin>>Branch;
      cout<<"\nSemster:";
      cin>>Semester;
}

void student::pack()
{
      string sem;
      stringstream out;
      out << Semester;
      sem = out.str(); 
      buffer.erase();
      buffer=USN+'|'+Name+'|'+Branch+'|'+sem+'$'+'\n';           
}    

void student::write_to_file()
{
      int pos;   
      fstream file;
      file.open("1.txt",ios::out|ios::app);
      pos=file.tellp();
      file<<buffer;
      file.close();
      rrn_list[++count]=pos;
}

void student::unpack()
{
     
      string sem;
      int ch=1,i=0;
      USN.erase();     
      while (buffer[i]!='|')
        USN+=buffer[i++];          
     
      Name.erase();
      i++;
      while (buffer[i]!='|')
        Name+=buffer[i++];   
     
      Branch.erase();  
      i++;
      while (buffer[i]!='|')
        Branch+=buffer[i++];
     
      sem.erase();     
      i++;
      while (buffer[i]!='$')
        sem+=buffer[i++];
      istringstream out(sem);
      out>>Semester;
           
}

void student::create_rrn()
{
      ifstream file;
      int pos;
      count=-1;
      file.open("1.txt",ios::in);
      while (!file.eof())
      {
            pos=file.tellg();      
            buffer.erase();        
            getline(file,buffer);
            rrn_list[++count]=pos;       
      }
      file.close();    
}

void student::search_by_rrn(int rrn)
{
      int pos=-1;
      fstream file;
      if (rrn>count)    cout<<"\n Not Found";
      else{
      buffer.erase();  
      file.open("1.txt");
      pos=rrn_list[rrn];
      file.seekp(pos,ios::beg);
      getline(file,buffer);
      cout<<"\n"<<buffer<<"\n" ;
      }
}

     
int main()
{
      int choice,rrn;
      student s1;
     
      s1.create_rrn();
     
      while(1){
      cout <<"\nMain Menu\n 1.Add  \n\n 2.Search 3.EXIT\n\nEnter the choice:";
      cin>>choice;     
      switch (choice)
      {
            case 1: cout<<"Data\n";
                  s1.read_data();
                  s1.pack();             
                  s1.write_to_file();
                  break;
            case 2: cout <<"\n\nEnter the RRN";
                  cin>>rrn;
                  s1.search_by_rrn(rrn);
                  break;
            case 3: return 0;
            default:cout<<"\n\nWrong Choice";
                  break;
      }}
}
     
     
           
 

Fs lab program for fixed length record

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
using namespace std;
class student
{
  public:
      string USN;
      string Name;
      string Branch;
      int Semester;
      string buffer;

      void read_data();
      void pack();
      void write_to_file();
      void unpack();
      int search(string);
      int delete_from_file(string);
      void modify(string);
};
void student::read_data()
{
      cout<<"\nUsn:";
      cin>>USN;
      cout<<"\nName:";
      cin>>Name;
      cout<<"\nBranch:";
      cin>>Branch;
      cout<<"\nSemster:";
      cin>>Semester;
}
void student::pack()
{
      string sem,temp;
      stringstream out;
      out << Semester;
      sem = out.str();
      temp.erase();    
      temp+=USN+'|'+Name+'|'+Branch+'|'+sem;
      for(;temp.size()<100;) temp+='$';
      buffer+=temp+'\n';
     
}    

void student::write_to_file()
{
      fstream file;
      file.open("1.txt",ios::out|ios::app);
      file<<buffer;
      file.close();
}

void student::unpack()
{
     
      string sem;
      int ch=1,i=0;
      USN.erase();     
      while (buffer[i]!='|')
        USN+=buffer[i++];          
     
      Name.erase();
      i++;
      while (buffer[i]!='|')
        Name+=buffer[i++];   
     
      Branch.erase();  
      i++;
      while (buffer[i]!='|')
        Branch+=buffer[i++];
     
      sem.erase();     
      i++;
      while (buffer[i]!='$')
        sem+=buffer[i++];
      istringstream out(sem);
      out>>Semester;
           
}

int student::search(string key)
{
      ifstream file;
      int flag=0, pos=0;
      file.open("1.txt",ios::in);
      while (!file.eof())
      {
            buffer.erase();        
            getline(file,buffer);
            unpack();
            if (key==USN) {cout<<"\nFound the key. The record is  "<<buffer;pos=file.tellg(); flag=1;return pos;}
      }
      file.close();    
      if (!flag) {cout<<"\n Not Found \n\n"; return pos;}
     
}

int student::delete_from_file(string key)
{
      fstream file;
      char del_mark='*',t;
      int pos,flag=0;
      pos=search(key);
      if (pos){  
            file.open("1.txt");
            pos-=101; //skip the $$$$$$ and \n characters
            file.seekp(pos,ios::beg);
            file.put(del_mark);                      
            flag=1;
            }
      file.close();    
      if (!flag) return 0;
      else return 1;
           
}          

void student::modify(string key)
{
      int choice;
      if (delete_from_file(key)){
      cout<<"\n What to modify?";
      cin>>choice;
      switch(choice)
      {
            case 1: cout<<"\nUSN:"; cin>>USN; break;
            case 2:     cout<<"\nName:";cin>>Name;break;
            case 3:     cout<<"\nBranch:";cin>>Branch;break;
            case 4:     cout<<"\nSemster:";cin>>Semester;break;
            default: cout <<"Wrong Choice";
      }
      buffer.erase();
      pack();
      write_to_file();
      }
}
     
int main()
{
      int count,choice,len,i;
      student s1;
      string key;
      cout <<"\nMain Menu\n 1.Add \n\n 2.Delete \n\n 3.Modify \n\n 4.Search \n\nEnter the choice:";
      cin>>choice;
      switch (choice)
      {
            case 1: cout<<"\n\nhow many records to insert?\n";
                  cin>>count;
                  for (i=0;i<count;i++)
                  {
                        cout<<"Data\n";
                        s1.read_data();
                        s1.pack();             
                  }
                  s1.write_to_file();
                  break;
            case 2: cout <<"\n\nEnter the key";
                  cin>>key;
                  i=s1.delete_from_file(key);
                  break;
            case 3: cout <<"\n\nEnter the key";
                  cin>>key;
                  s1.modify(key);
                  break;
            case 4: cout <<"\n\nEnter the key";
                  cin>>key;
                  i=s1.search(key);
                  break;
            default: cout<<"\n\nWrong Choice";
      }
      return 0;  
}