Banker's Algorithm

Wrote by Unknown 07:38 Post Comment




C Program For Banker's Algorithm

Source Code:


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

void copy(int a[20][20],int b[20][20],int c,int d)
{
 int l1,l2;
 for(l1=1;l1<=d;l1++)
 {
 for(l2=1;l2<=c;l2++)
 {
 b[l1][l2]=a[l1][l2];
 }
 }
}

void show(int a[20][20],int c,int d)
{
 int l1,l2;
 for(l1=1;l1<=c;l1++)
 {
 for(l2=1;l2<=d;l2++)
 {
 printf("  %d",a[l1][l2]);
 }
 printf("\n");
 }
 printf("\n----------------------\n");
}

void copy2(int a[20],int b[20],int c)
{
 int l1;
 for(l1=1;l1<=c;l1++)
 {
 b[l1]=a[l1];
 }
}


void show2(int a[20],int c)
{
 int l1;
 for(l1=1;l1<=c;l1++)
 {
 printf("  %d",a[l1]);
 }
 printf("\n-------------------------\n");
}

int safetyalgo(int m,int n,int max[20][20],int all[20][20],int need[20][20],
int ava[20],int seq[20],int send)
{
 int work[20],finish[20],c=0,f=0,f0=0,sem,i,j,g,ml,cd,s=0,ct=0;
 
 for(i=1;i<=m;i++)
 {
 work[i]=ava[i];
 }

 for(i=1;i<=n;i++)
 {
 finish[i]=0;
 }
 printf("\nMaximum need\n");
 show(max,n,m);
 printf("\nAllocations\n");
 show(all,n,m);
 printf("\nAvailable\n");
 show2(work,m);
 printf("\nNeed\n");
 show(need,n,m);
 if(send==0)
 printf("\nSteps to check if current system is safe or not\n");
 else
 printf("\nSteps for allocating resources\n");
 while(f!=1 && f0!=1)
 {
 cd=0;
 for(i=1;i<=n;i++)
 {
 if(need[i][1]<=work[1] && need[i][2]<=work[2] && need[i][3]<=work[3] && finish[i]==0)
 {
 for(j=1;j<=m;j++)
 {
 work[j]=work[j]+all[i][j];
 }
 finish[i]=1;
 s++;
 seq[s]=i;
 printf("\n\nStep=%d",s);
 printf("\nwork\n");
 show2(work,m);
 printf("\nfinish\n");
 show2(finish,n);
 cd=0;
 i=0;
 }
 else
 cd++;
 if(cd==n)
 {
 f0=1;
 break;
 }
 c=0;
 for(ml=1;ml<=n;ml++)
 {
 if(finish[ml]==1)
 {
 c++;
 }
 }
 if(c==n)
 {
 f=1;
 break;
 }
 }
 }
 if(f==1)
 {
 sem=1;
 }
 if(f0==1)
 {
 sem=0;
 }
 return sem;
}
 
int ralgo(int m,int n,int max[20][20],int all[20][20],int need[20][20],
int ava[20],int req[20],int seq[20],int id)
{
 int i,j,get1;
 if(req[1]<=need[id][1] && req[2]<=need[id][2] && req[3]<=need[id][3])
 {
 if(req[1]<=ava[1] && req[2]<=ava[2] && req[3]<=ava[3])
 {
 for(j=1;j<=m;j++)
 {
 need[id][j]=need[id][j]-req[j];
 all[id][j]=all[id][j]+req[j];
 ava[j]=ava[j]-req[j];
 }
 }
 else
 {
 printf("\nError2\n");
 exit(0);
 }
 }
 else
 {
 printf("Error1\n");
 exit(0);
 }
 get1=safetyalgo(m,n,max,all,need,ava,seq,1);
 return get1;
}

void main()
{
 printf("\n------------BANKER'S ALGORITHM-----------\n");
 int m,n,max[20][20],all[20][20],need[20][20],ava[20],work[20],i,j,get,req[20],
 id,get1,seq[20];
 int m1,n1,max1[20][20],all1[20][20],need1[20][20],ava1[20],work1[20],
 finish1[20],req1[20],id1;
 printf("\nEnter number of processes:");
 scanf("%d",&n);
 m=3;
 printf("\nNumber of resource types=3 (defined by the system)");
 for(i=1;i<=n;i++)
 {
 for(j=1;j<=m;j++)
 {
 printf("\nEnter resource-%d's maximum need of process P%d:",j,i);
 scanf("%d",&max[i][j]);
 }
 }

 for(i=1;i<=n;i++)
 {
 for(j=1;j<=m;j++)
 {
 printf("\nEnter allocation of resource-%d for process P%d:",j,i);
 scanf("%d",&all[i][j]);
 }
 }
 
 for(i=1;i<=m;i++)
 {
 printf("\nEnter availability of resource-%d in system:",i);
 scanf("%d",&ava[i]);
 }
 
 printf("\nEnter the process id of the requesting process:");
 scanf("%d",&id);
 printf("\nEnter number of requests for each processes:");
 for(i=1;i<=m;i++)
 {
 scanf("  %d",&req[i]);
 }
 for(i=1;i<=n;i++)
 {
 for(j=1;j<=m;j++)
 {
 need[i][j]=max[i][j]-all[i][j];
 }
 }

 id1=id;
 n1=n;
 m1=m;
 copy(max,max1,m,n);
 copy(need,need1,m,n);
 copy(all,all1,m,n);
 copy2(ava,ava1,m);
 copy2(work,work1,m);
 copy2(req,req1,m);
 printf("\nChecking if the present system is safe or not by safety algorithm\n");
 get=safetyalgo(m,n,max,all,need,ava,seq,0);
 if(get==0)
 printf("\nThe system is in unsafe state,resources could not be allocated to the processes\n");
 else
 {
 printf("\nThe present system is in safe state.resources could be allocated\n");
 printf("\nSafe Sequence\n");
 for(i=1;i<=n;i++)
 {
 printf("  P%d",seq[i]);
 }
 printf("\nAllocating resources by resource allocation algorithm\n");
 get1=ralgo(m1,n1,max1,all1,need1,ava1,req1,seq,id1);
 if(get1==1)
 {
 printf("\nAllocation successful\n");
 printf("\nSafe Sequence\n");
 for(i=1;i<=n;i++)
 {
 printf("  P%d",seq[i]);
 }
 }
 else
 printf("\nSystem leads to unsafe state.Allocation should be rolled back\n");
 }
}

OUTPUT
[Rakesh@localhost ~]$ cc -o k bankers.c
[Rakesh@localhost ~]$ ./k

------------BANKER'S ALGORITHM-----------

Enter number of processes:5

Number of resource types=3 (defined by the system)
Enter resource-1's maximum need of process P1:7

Enter resource-2's maximum need of process P1:5

Enter resource-3's maximum need of process P1:3

Enter resource-1's maximum need of process P2:3

Enter resource-2's maximum need of process P2:2

Enter resource-3's maximum need of process P2:2

Enter resource-1's maximum need of process P3:9

Enter resource-2's maximum need of process P3:0

Enter resource-3's maximum need of process P3:2

Enter resource-1's maximum need of process P4:2

Enter resource-2's maximum need of process P4:2

Enter resource-3's maximum need of process P4:2

Enter resource-1's maximum need of process P5:4

Enter resource-2's maximum need of process P5:3

Enter resource-3's maximum need of process P5:3

Enter allocation of resource-1 for process P1:0

Enter allocation of resource-2 for process P1:1

Enter allocation of resource-3 for process P1:0

Enter allocation of resource-1 for process P2:2

Enter allocation of resource-2 for process P2:0

Enter allocation of resource-3 for process P2:0

Enter allocation of resource-1 for process P3:3

Enter allocation of resource-2 for process P3:0

Enter allocation of resource-3 for process P3:2

Enter allocation of resource-1 for process P4:2

Enter allocation of resource-2 for process P4:1

Enter allocation of resource-3 for process P4:1

Enter allocation of resource-1 for process P5:0

Enter allocation of resource-2 for process P5:0

Enter allocation of resource-3 for process P5:2

Enter availability of resource-1 in system:3

Enter availability of resource-2 in system:3

Enter availability of resource-3 in system:2

Enter the process id of the requesting process:2

Enter number of requests for each processes:1 0 2

Checking if the present system is safe or not by safety algorithm

Maximum need
  7  5  3
  3  2  2
  9  0  2
  2  2  2
  4  3  3

----------------------

Allocations
  0  1  0
  2  0  0
  3  0  2
  2  1  1
  0  0  2

----------------------

Available
  3  3  2
-------------------------

Need
  7  4  3
  1  2  2
  6  0  0
  0  1  1
  4  3  1

----------------------

Steps to check if current system is safe or not


Step=1
work
  5  3  2
-------------------------

finish
  0  1  0  0  0
-------------------------


Step=2
work
  7  4  3
-------------------------

finish
  0  1  0  1  0
-------------------------


Step=3
work
  7  5  3
-------------------------

finish
  1  1  0  1  0
-------------------------


Step=4
work
  10  5  5
-------------------------

finish
  1  1  1  1  0
-------------------------


Step=5
work
  10  5  7
-------------------------

finish
  1  1  1  1  1
-------------------------

The present system is in safe state.resources could be allocated
Safe Sequence
  P2  P4  P1  P3  P5
Allocating resources by resource allocation algorithm

Maximum need
  7  5  3
  3  2  2
  9  0  2
  2  2  2
  4  3  3

----------------------

Allocations
  0  1  0
  3  0  2
  3  0  2
  2  1  1
  0  0  2

----------------------

Available
  2  3  0
-------------------------

Need
  7  4  3
  0  2  0
  6  0  0
  0  1  1
  4  3  1

----------------------

Steps for allocating resources


Step=1
work
  5  3  2
-------------------------

finish
  0  1  0  0  0
-------------------------


Step=2
work
  7  4  3
-------------------------

finish
  0  1  0  1  0
-------------------------


Step=3
work
  7  5  3
-------------------------

finish
  1  1  0  1  0
-------------------------


Step=4
work
  10  5  5
-------------------------

finish
  1  1  1  1  0
-------------------------


Step=5
work
  10  5  7
-------------------------

finish
  1  1  1  1  1
-------------------------

Allocation successful

Safe Sequence
  P2  P4  P1  P3  P5
[Rakesh@localhost ~]$ ./k

------------BANKER'S ALGORITHM-----------

Enter number of processes:5

Number of resource types=3 (defined by the system)
Enter resource-1's maximum need of process P1:7

Enter resource-2's maximum need of process P1:5

Enter resource-3's maximum need of process P1:3

Enter resource-1's maximum need of process P2:3

Enter resource-2's maximum need of process P2:2

Enter resource-3's maximum need of process P2:2

Enter resource-1's maximum need of process P3:9

Enter resource-2's maximum need of process P3:0

Enter resource-3's maximum need of process P3:2

Enter resource-1's maximum need of process P4:2

Enter resource-2's maximum need of process P4:2

Enter resource-3's maximum need of process P4:2

Enter resource-1's maximum need of process P5:4

Enter resource-2's maximum need of process P5:3

Enter resource-3's maximum need of process P5:3

Enter allocation of resource-1 for process P1:0

Enter allocation of resource-2 for process P1:1

Enter allocation of resource-3 for process P1:0

Enter allocation of resource-1 for process P2:3

Enter allocation of resource-2 for process P2:0

Enter allocation of resource-3 for process P2:2

Enter allocation of resource-1 for process P3:3

Enter allocation of resource-2 for process P3:0

Enter allocation of resource-3 for process P3:2

Enter allocation of resource-1 for process P4:2

Enter allocation of resource-2 for process P4:1

Enter allocation of resource-3 for process P4:1

Enter allocation of resource-1 for process P5:0

Enter allocation of resource-2 for process P5:0

Enter allocation of resource-3 for process P5:2

Enter availability of resource-1 in system:2

Enter availability of resource-2 in system:3

Enter availability of resource-3 in system:0

Enter the process id of the requesting process:1

Enter number of requests for each processes:0 2 0


Checking if the present system is safe or not by safety algorithm

Maximum need
  7  5  3
  3  2  2
  9  0  2
  2  2  2
  4  3  3

----------------------

Allocations
  0  1  0
  3  0  2
  3  0  2
  2  1  1
  0  0  2

----------------------

Available
  2  3  0
-------------------------

Need
  7  4  3
  0  2  0
  6  0  0
  0  1  1
  4  3  1

----------------------

Steps to check if current system is safe or not


Step=1

work
  5  3  2
-------------------------

finish
  0  1  0  0  0
-------------------------


Step=2

work
  7  4  3
-------------------------

finish
  0  1  0  1  0
-------------------------


Step=3

work
  7  5  3
-------------------------

finish
  1  1  0  1  0
-------------------------


Step=4
work
  10  5  5
-------------------------

finish
  1  1  1  1  0
-------------------------


Step=5
work
  10  5  7
-------------------------

finish
  1  1  1  1  1
-------------------------

The present system is in safe state.resources could be allocated

Safe Sequence
  P2  P4  P1  P3  P5

Allocating resources by resource allocation algorithm

Maximum need
  7  5  3
  3  2  2
  9  0  2
  2  2  2
  4  3  3

----------------------

Allocations
  0  3  0
  3  0  2
  3  0  2
  2  1  1
  0  0  2

----------------------

Available
  2  1  0
-------------------------

Need
  7  2  3
  0  2  0
  6  0  0
  0  1  1
  4  3  1

----------------------

Steps for allocating resources

System leads to unsafe state.Allocation should be rolled back

Tags: OS Related C progeams

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