worstfit.c

// worst fit
// Roll: 313
// Anirudh
#include<stdio.h>
// Function to allocate memory to blocks as per worst fit
// algorithm
void worstFit(int blockSize[], int m, int processSize[],int n)
{
// Stores block id of the block allocated to a
// process
int allocation[n];
// Initially no block is assigned to any process
for(int i = 0; i < n; i++)
{
allocation[i] = -1;
}
// pick each process and find suitable blocks
// according to its size ad assign to it
for (int i=0; i<n; i++)
{
// Find the best fit block for current process
int wstIdx = -1;
for (int j=0; j<m; j++)
{
if (blockSize[j] >= processSize[i])
{
if (wstIdx == -1)
wstIdx = j;
else if (blockSize[wstIdx] < blockSize[j])
wstIdx = j;
}
}
// If we could find a block for current process
if (wstIdx != -1)
{
// allocate block j to p[i] process
allocation[i] = wstIdx;
// Reduce available memory in this block.
blockSize[wstIdx] -= processSize[i];
}
}
printf("\nProcess No.\tProcess Size\tBlock no.\n");
for (int i = 0; i < n; i++)
{
printf(" %d\t\t%d\t\t",i+1,processSize[i]);
if (allocation[i] != -1)
printf("%d",allocation[i] + 1);
else
printf("Not Allocated");
printf("\n");
}
}
// Driver code
int main()
{
int blockSize[] = {100, 500, 200, 300, 600};
int processSize[] = {212, 417, 112, 426};
int m = sizeof(blockSize)/sizeof(blockSize[0]);
int n = sizeof(processSize)/sizeof(processSize[0]);
worstFit(blockSize, m, processSize, n);
return 0 ;
}


//output

Process No.	Process Size	Block no.
 1		212		5
 2		417		2
 3		112		5
 4		426		Not Allocated