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# Source code for banker's algorithm with RANDOM ALLOCATION in C LANGUAGE.

Posted on 2004-09-30
Medium Priority
22,491 Views
hi guys,
im searching for a source code(written in c) for banker's algorithm simulation with RANDOM ALLOCATION. does anybody of u know where can i find this(the program should be in c-language,..no java code at all).

Thanks

Johnny
0
Question by:johnnybuc
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LVL 34

Accepted Solution

Dave_Dietz earned 2000 total points
ID: 12326132
Found this with a simple Google search:

/* Banker's algorithm implementation by Chuck Liang
Hofstra University Computer Science
*/

#include<stdio.h>
/* NPROC = number of processes, NRES = number of resources */
#define NPROC 5
#define NRES  3
#define BOOL int

// add vector B to vector A
void vadd(int *A, int *B, int sgn)  //flag 1 = add,  -1 = subtract
{
int i;
for(i=0;i<NRES;i++) A[i] = A[i] + (sgn * B[i]);
}

// determine if A<B
BOOL vcmp(int *A, int *B)
{ int i, j;
j = 1;
for(i=0;j && (i<NRES);i++) if (A[i]>B[i]) j = 0;
return j;
}

// print a NPROCxNRES array
void print2d(int ** A)
{ int i, j;
for(i=0;i<NPROC;i++)
{ printf("P%d  ",i);
for(j=0;j<NRES;j++) printf("%d ",A[i][j]);
printf("\n");
}
printf("\n");
} // print2d

// determine if a state is safe
BOOL safe(int * Finish,
int * Available,
int * Work,
int** Allocation,
int** Need
)
{ int i, j;
// find i such that finish[i] = 0 and need[i] < work
for(j=0;j<NRES;j++) printf("%d ",Work[j]); printf("  (work)\n");
i = 0;   // proc counter
j = 1;   // all finished
while ((i<NPROC) && (Finish[i] || (!vcmp(Need[i],Work))))
{
j = j && Finish[i];
i++;
}
if (i==NPROC) return j;
// simulate acquisition and release of resources
printf("Process %d can finish\n\n",i);
Finish[i] = 1;
return safe(Finish,Available,Work,Allocation,Need);
} // safe

// determine if a request by a process will lead to a safe state
BOOL grant(int pid,
int * Request,
int * Available,
int** Allocation,
int** Need)
{   int i;
int Finish[NPROC];
int Work[NRES];
for(i=0;i<NPROC;i++) Finish[i] = 0;
if (!vcmp(Request,Need[pid])) return 0;
if (!vcmp(Request,Available)) return 0;
// simulate acquisition
for(i=0;i<NRES;i++) Work[i] = Available[i];
printf("Allocation:\n"); print2d(Allocation);
printf("Need:\n"); print2d(Need);
return safe(Finish,Available,Work,Allocation,Need);
}

// main function implements example in dinosaur book
int main()
{ int i, j;
int Av[NRES];      // available
int Req[NRES];     // request
int Work[NRES];
int Finish[NPROC];
int ** Al;  int ** Nd;  // allocation and need are dynamic 2d arrays
Al = (int **) malloc(sizeof(int*)*NPROC);
for(i=0;i<NPROC;i++) Al[i] = (int*) malloc(sizeof(int)*NRES);
Nd = (int **) malloc(sizeof(int*)*NPROC);
for(i=0;i<NPROC;i++) Nd[i] = (int*) malloc(sizeof(int)*NRES);

//implicit: initially Av[0] = 10;  Av[1] = 5;  Av[2] = 7;

Al[0][0] = 0; Al[0][1] = 1; Al[0][2] = 0;
Al[1][0] = 2; Al[1][1] = 0; Al[1][2] = 0;
Al[2][0] = 3; Al[2][1] = 0; Al[2][2] = 2;
Al[3][0] = 2; Al[3][1] = 1; Al[3][2] = 1;
Al[4][0] = 0; Al[4][1] = 0; Al[4][2] = 2;

Nd[0][0] = 7; Nd[0][1] = 4; Nd[0][2] = 3;
Nd[1][0] = 1; Nd[1][1] = 2; Nd[1][2] = 2;
Nd[2][0] = 6; Nd[2][1] = 0; Nd[2][2] = 0;
Nd[3][0] = 0; Nd[3][1] = 1; Nd[3][2] = 1;
Nd[4][0] = 4; Nd[4][1] = 3; Nd[4][2] = 1;

Av[0] = 3; Av[1] = 3; Av[2] = 2;

for(i=0;i<NRES;i++) Work[i] = Av[i];
for(i=0;i<NPROC;i++) Finish[i] = 0;
if (safe(Finish,Av,Work,Al,Nd)) printf("state is safe\n");
else printf("state is not safe\n");

// simulate request for 1,0,2 by P1:
Req[0] = 1; Req[1] = 0; Req[2] = 2;
if (grant(1,Req,Av,Al,Nd)) printf("P1 can ");
else printf("P1 cannot ");
printf("be granted request for 1,0,2\n");

// simulate request for 0,2,0 by P0:
Req[0] = 0; Req[1] = 2; Req[2] = 0;
if (grant(0,Req,Av,Al,Nd)) printf("P0 can ");
else printf("P0 cannot ");
printf("be granted request for 0,2,0\n");

for(i=0;i<NPROC;i++) { free(Al[i]); free(Nd[i]); }
free(Al);  free(Nd);
exit(0);
}

Dave Dietz
0

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