Program for Banker's Algorithm. 
 

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#include<process.h>
int n,m,avai[5],need[5][3],alloc[5][3];
int safe(void);

void main()
{
int i,j,k,flag[5],seq[5],resor[3],claim[5][3];
clrscr();
printf("Enter no. of resource types:");
scanf("%d",&m);
printf("Enter no. of processes:");
scanf("%d",&n);
printf("Enter total no. of instances for each resource:\n");
for(i=0;i<m;i++)
scanf("%d",&resor[i]);
printf("Enter maximum allocation for each process:\n");
for(i=0;i<n;i++)
for(j=0;j<m;j++)
scanf("%d",&claim[i][j]);
printf("Enter allocation for each process at snapshot T0:\n");
for(i=0;i<n;i++)
for(j=0;j<m;j++)
scanf("%d",&alloc[i][j]);
for(j=0;j<m;j++)
{
k=0;
for(i=0;i<n;i++)
k=k+alloc[i][j];
avai[j]=resor[j]-k;
}
for(i=0;i<n;i++)
{
for(j=0;j<m;j++)
need[i][j]=claim[i][j]-alloc[i][j];
flag[i]=1;
seq[i]=-1;
}

printf("\n Resources Available\n");
for(j=0;j<m;j++)
printf("R%d\t%d\t %d\n",j,resor[j],avai[j]);
printf("\n CLAIM ALLOCATION NEED\n");
for(i=0;i<n;i++)
{
for(j=0;j<m;j++)
printf(" %d ",claim[i][j]);
printf("\t");
for(j=0;j<m;j++)
printf(" %d ",alloc[i][j]);
printf("\t");
for(j=0;j<m;j++)
printf(" %d ",need[i][j]);
printf("\n");
}

for(k=0;k<n;k++)
{
for(i=0;i<n;i++)
{
if(flag[i])
{
for(j=0;j<m;j++)
if(alloc[i][j]+need[i][j]>claim[i][j])
{
printf("\t%d",i);
perror("\nError......... Total Request more than claim");
getch();
exit(1);
}
else if(need[i][j]>avai[j]) //wait process
goto next;
else
for(j=0;j<m;j++)
{ //simulate allocation
alloc[i][j]=alloc[i][j]+need[i][j];
avai[j]=avai[j]-need[i][j];
}

if(safe()) //carry out allocation
{
printf("\nP%d safe....",i);
for(j=0;j<m;j++)
{
avai[j]=avai[j]-alloc[i][j];
alloc[i][j]=0;
need[i][j]=0;
flag[i]=0;
}
seq[k++]=i;
}
else //suspend
{
for(j=0;j<m;j++)
{
alloc[i][j]=alloc[i][j]-need[i][j];
avai[j]=avai[j]+need[i][j];
}
flag[i]=1;
printf("\nP%d unsafe....allocation restored",i);
}
if(i==(n-1)) k--;
}
next:
}
}
printf("\nSequence of Process execution using BANKERS ALGO:\n");
for(i=0;i<n;i++)
printf("P%d\t",seq[i]);
getch();
}

int safe(void)
{
int p,q,r,curravai[5],finish[5],safe;
for(r=0;r<m;r++)
curravai[r]=avai[r];
for(q=0;q<n;q++)
finish[q]=0;

for(q=0;q<n;q++)
for(r=0;r<m;r++)
if((!finish[q])&&(need[q][r]<=curravai[r]))
{
curravai[r]=curravai[r]+alloc[q][r];
finish[q]=1;
}
else
{
safe=0;
for(p=0;p<n;p++)
if(finish[p])
safe=1;
}
return(safe);
}

 

Enter no. of resource types:3
Enter no. of processes:5
Enter total no. of instances for each resource:
10 5 7
Enter maximum allocation for each process:
7 5 3
3 2 2
9 0 2
2 2 2
4 3 3
Enter allocation for each process at snapshot T0:
0 1 0
2 0 0
3 0 2
2 1 1
0 0 2

Resources Available
R0 10 3
R1 5 3
R2 7 2

CLAIM ALLOCATION NEED
7 5 3 0 1 0 7 4 3
3 2 2 2 0 0 1 2 2
9 0 2 3 0 2 6 0 0
2 2 2 2 1 1 0 1 1
4 3 3 0 0 2 4 3 1

P1 Safe...........
P3 Safe...........
P4 Safe...........
P0 Safe...........
P2 Safe...........

Sequence of Process execution using BANKERS ALGO:
P1 P3 P4 P0 P2