/*
Consider a system with 'n' processes and 'm' resource type. Accept number of
instances for every resource type. For each process accept the allocation
and maximum requirement matrices. Write a program to check if the given
request of a process can be granted immediately or not.
*/
#include<stdio.h>
int A[10][10],M[10][10],N[10][10],Av[10],Safe[10],Finish[10],R[10][10],nor,nop;
void AcceptData(int X[][10])
{
int i,j;
for(i=0;i<nop;i++)
{
printf("P%d\n",i);
for(j=0;j<nor;j++)
{
printf("%c: ",65+j);
scanf("%d",&X[i][j]);
}
}
}
void AcceptAvailability()
{
int i;
for(i=0;i<nor;i++)
{
printf("%c: ",65+i);
scanf("%d",&Av[i]);
}
}
void AcceptRequest(int R[][10])
{
int i;
for(i=0;i<nor;i++)
{
printf("%c: ",65+i);
scanf("%d",&R[i]);
}
}
void DisplayData()
{
int i,j;
printf("\n\tAllocation\t\tMax\t\tNeed\n");
printf("\t");
for(i=0;i<3;i++)
{
for(j=0;j<nor;j++)
printf("%4c",65+j);
printf("\t");
}
for(i=0;i<nop;i++)
{
printf("\nP%d\t",i);
for(j=0;j<nor;j++)
printf("%4d",A[i][j]);
printf("\t");
for(j=0;j<nor;j++)
printf("%4d",M[i][j]);
printf("\t");
for(j=0;j<nor;j++)
printf("%4d",N[i][j]);
}
printf("\nAvailable\n");
for(j=0;j<nor;j++)
printf("%4d",Av[j]);
}
void CalcNeed()
{
int i,j;
for(i=0;i<nop;i++)
for(j=0;j<nor;j++)
N[i][j] = M[i][j] - A[i][j];
}
int checkNeed(int pno)
{
int i;
for(i=0;i<nor;i++)
if(N[pno][i] > Av[i])
return(0);
return(1);
}
int checkRequest()
{
int i;
for(i=0;i<nor;i++)
if(R[0][i] > Av[i])
return(0);
return(1);
}
void Banker()
{
int i=0,j=0,k=0,flag=0;
while(flag<2)
{
if(!Finish[i])
{
printf("\nNeed%d(",i);
for(j=0;j<nor;j++)
printf("%d,",N[i][j]);
if(!checkNeed(i))
{
printf("\b)>Available(");
for(j=0;j<nor;j++)
printf("%d,",Av[j]);
printf("\b)");
printf("\nNeed Cannot be satisfied, consider next process");
}
else
{
printf("\b)<=Available(");
for(j=0;j<nor;j++)
printf("%d,",Av[j]);
printf("\b)");
printf("\nNeed can be satisfied, so allocate required resources");
printf("\nAllocation%d\tAvailable\tNeed%d\n",i,i);
for(j=0;j<nor;j++)
{
A[i][j] = M[i][j];
Av[j] -= N[i][j];
N[i][j] = 0;
}
for(j=0;j<nor;j++)
printf("%4d",A[i][j]);
printf("\t");
for(j=0;j<nor;j++)
printf("%4d",Av[j]);
printf("\t");
for(j=0;j<nor;j++)
printf("%4d",N[i][j]);
printf("\nAfter P%d terminates it will release all its resources",i);
printf("\nAllocation%d\tAvailable\tNeed%d\n",i,i);
for(j=0;j<nor;j++)
{
Av[j] += A[i][j];
A[i][j] = 0;
}
for(j=0;j<nor;j++)
printf("%4d",A[i][j]);
printf("\t");
for(j=0;j<nor;j++)
printf("%4d",Av[j]);
printf("\t");
for(j=0;j<nor;j++)
printf("%4d",N[i][j]);
Safe[k++] = i;
Finish[i]=1;
}
}
if((i+1)%nop == 0)
flag++;
i=(i+1)%nop;
}
if(k==nop)
{
printf("\nSystem is in safe state...");
printf("\nSafe Sequence: ");
for(i=0;i<k;i++)
printf("P%d->",Safe[i]);
printf("\b\b ");
}
else
{
printf("\nSystem is in not safe state...");
}
}
void main()
{
printf("\nEnter No.of Processes & No.of Resources: ");
scanf("%d %d",&nop,&nor);
printf("Enter Allocation\n");
AcceptData(A);
printf("Enter Max Requirement\n");
AcceptData(M);
printf("Enter Availability\n");
AcceptAvailability();
CalcNeed();
DisplayData();
Banker();
printf("Enter the new Request from process");
AcceptRequest(R);
if((checkRequest())==1)
printf("\nNew Request for the process can be granted");
else
printf("\nNew Request for the process canot be granted");
}
