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bankers.c
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bankers.c
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#include<stdio.h>
#include<stdlib.h>
#include<stdbool.h>
#include<time.h>
int m,n,i,j;
struct bank
{
int max[10];
int pid;
int alloc[10];
int need[10];
} p[10];
void input(struct bank *s, int avail[10])
{
printf("\nEnter available:\t");
for(i=0;i<n;i++)
{
s[i].pid=i;
}
for(i=0;i<m;i++)
{
scanf("%d",&avail[i]);
}
printf("\nEnter max matrix:\t");
for(i=0;i<n;i++)
{
for(j=0;j<m;j++)
{
// printf("\nEnter max[%d][%d]:\t",i,j);
scanf("%d",&s[i].max[j]);
}
}
printf("\nEnter allocation matrix:\t");
for(i=0;i<n;i++)
for(j=0;j<m;j++)
{
//printf("\nEnter allocation[%d][%d]:\t",i,j);
scanf("%d",&s[i].alloc[j]);
s[i].need[j]=s[i].max[j]-s[i].alloc[j];//calculating need
}
}
void display(struct bank *s,int avail[10])
{
printf("\nAvailable:");
for(i=0;i<m;i++)
{
printf("%d\t",avail[i]);
}
printf("\n\n\nMax:\n");
for(i=0;i<n;i++)
{
printf("\nP%d\t",s[i].pid);
for(j=0;j<m;j++)
printf("%d\t",s[i].max[j]);
}
printf("\n\n\nAllocation:\n");
for(i=0;i<n;i++)
{
printf("\nP%d\t",s[i].pid);
for(j=0;j<m;j++)
printf("%d\t",s[i].alloc[j]);
}
printf("\n\n\nNeed:\n");
for(i=0;i<n;i++)
{
printf("\nP%d\t",s[i].pid);
for(j=0;j<m;j++)
printf("%d\t",s[i].need[j]);
}
}
bool safety(struct bank *s, int avail[10])
{
int work[m],finish[n],count=0,safe[n];
for(i=0;i<m;i++)
work[i]=avail[i];//setting work=available
for(i=0;i<n;i++)
finish[i]=0;//setting finish as false
do{
bool exist=false;//to see if i exists
for(i=0;i<n;i++)
{
//("\nFinish[%d]=%d",i,finish[i]);
if(finish[i]==0)
{
for(j=0;j<m;j++)
{
//printf("\nNeed[%d]:%d\tWork[%d]:%d",j,s[i].need[j],j,work[j]);
if(s[i].need[j]>work[j])
break;
}
if(j==m)
{
printf("\nP%d over",i);
for(j=0;j<m;j++)
{
work[j]+=s[i].alloc[j];
}
finish[i]=1;
safe[count]=s[i].pid;
exist=true;
count++;
printf("\n%d processes over",count);
}
}
}
printf("\ni exists? %d",exist);
if(exist==false)
return false;
}while(count<n);
printf("\nSafe sequence:\t");
for(i=0;i<n;i++)
printf("P%d\t",safe[i]);
printf("\n");
return true;
}
void res_req(struct bank *s, int request[10],int pno,int avail[10])
{
for(i=0;i<m;i++)
{
if(request[i]>s[pno].need[i])
break;
}
if(i!=m)
printf("\nProcess has exceeded maximum claim!!\nResource cannot be granted\n");
else
{
printf("\nRequest within need");
for(i=0;i<m;i++)
{
if(request[i]>avail[i])
break;
}
if(i!=m)
printf("\nProcess must wait\nResources not available\n");
else
{
printf("\nYes the request can be granted\nChecking for safe state...");
for(i=0;i<m;i++)
{
avail[i]-=request[i];
s[pno].alloc[i]+=request[i];
s[pno].need[i]-=request[i];
}
display(s,avail);
if(safety(s,avail)==false)
printf("\nUnsafe state if this request is granted!\n");
else
{
printf("\nRequest granted leaves system in safe state\n");
}
}
}
}
void main()
{
int avail[10];
printf("\nEnter number of processes:\t");
scanf("%d",&n);
printf("\nEnter number of resource types:\t");
scanf("%d",&m);
struct bank *ptr=p;
input(ptr,avail);
display(ptr,avail);
if(safety(ptr,avail)==false)
{
printf("\nSystem is not in safe state!!\n");
}
else
{
int pno,request[m];
printf("\nEnter process no that requests:\t");
scanf("%d",&pno);
printf("\nEnter request:\t");
for(i=0;i<m;i++)
{
scanf("%d",&request[i]);
}
res_req(ptr,request,pno,avail);
}
}