Computer systems are with full of different types of resources that can only be

Question

Computer systems are with full of different types of resources that can only be used by one process at a time. For many applications, most of the processes need exclusive access to not one, but several resources. So, chances of deadlocks are more in such situations. Write a program in C to implement the deadlock detection algorithm with single resource of each type. The output of the program should indicate that whether there is a deadlock or not. In case there is a deadlock in the system, the program should identify all processes which are deadlocked.

Thank You

Explanation / Answer

For deadlock detection banker's algorithm is best example.So here we implementing banker;s algorithm.

/* Banker's Algorithm*/

#include<stdio.h>

int main()
{
   int fnd,flag,L,pro[4][5],np,nr,res[4][5],i,j,k=1,x[5],rs[5],av[5],t[5];
   int sum=0;
   printf("Please enter total number of processes : ");
   scanf("%d",&np);
   printf("Please enter total number of resources : ");
   scanf("%d",&nr);
   printf("Please enter claim Matrix ");
   for(i=1 ; i<=np; i++){
       printf("Process %d : ",i);
       for(j=1 ; j<=nr ; j++){
       scanf("%d",&res[i][j]);
       }
   }
   printf("Please Enter allocation Matrix ");

   for(i=1 ; i<=np; i++){
       printf("Process %d : ",i);
       for(j=1 ; j<=nr ; j++){
       scanf("%d",&pro[i][j]);
       }
   }
   printf("Please Enter total resources : ");
   for(i=1 ; i<=nr ; i++){
       scanf("%d",&rs[i]);}
   printf("Please Enter available resources : ");
   for(i=1 ; i<=nr ; i++){
       scanf("%d",&av[i]);
       t[i] = av[i];
   }
   for(i=1 ; i<=np; i++){
       sum=0;
       for(j=1 ; j<=nr ; j++){
       sum = sum + pro[i][j];
       }
       if(sum == 0){
       x[k] = i;
       k++;
       }
   }
   for(i=1 ; i<=np; i++){
       for(L=1 ; L<k ; L++){
       if(i!=x[L])
       {
       flag =1 ;
       for(j=1 ; j<=nr; j++){
       if(res[i][j]<t[j])
       {
           flag = 0;
           break;
       }
       }}
       if(flag == 1){
       x[k] = i;
       k++;
       for(j=1 ; j<=nr ; j++){
           t[j] = t[j] + pro[i][j];
       }
       }
   }}
   printf("Processes that occuring Deadlock : ");
   for(j=1 ; j<=np; j++){
       fnd=0;
       for(i=1; i<k; i++){
       if(j==x[i])
       fnd=1;
       }
       if(fnd == 0)
       printf("%d ",j);
   }
   getch();
return 0 ;
}

Output :
Enter total number of processes : 2
Enter total number of resources : 2
Please Enter claim Matrix :

Process 1 : 1 0

Process 2 : 0 1
Please enter allocation Matrix :

Process 1 : 1 0

Process 2 : 0 0
Enter total number of resources :
1 1

Enter available resources :
1 0
Processes causing deadlocks : 1

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