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BankersAlgo.cpp
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BankersAlgo.cpp
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#include<iostream>
using namespace std;
const int P = 5;const int R = 3;
void calculateNeed(int need[P][R], int maxm[P][R], int allot[P][R])
{ for (int i = 0 ; i < P ; i++)
for (int j = 0 ; j < R ; j++)
need[i][j] = maxm[i][j] - allot[i][j];
}
bool isSafe(int processes[], int avail[], int maxm[][R], int allot[][R])
{ int need[P][R], safeSeq[P], work[R];
calculateNeed(need, maxm, allot);
bool finish[P] = {false};
for (int i = 0; i < R ; i++)
work[i] = avail[i];
for (int i = 0; i < R ; i++)
cout<<work[i];
cout<<"\n";
int count = 0;
while (count < P)
{
bool found = false;
for (int p = 0; p < P; p++)
{
if (finish[p] == false)
{
int j;
for (j = 0; j < R; j++){
if (need[p][j] > work[j]){
break;
}
}
if (j == R)
{
for (int k = 0 ; k < R ; k++)
work[k] += allot[p][k];
safeSeq[count++] = p;
finish[p] = true;
found = true;
}
}
}
if (found == false)
{
cout << "System is not in safe state";
return false;
}
}
cout << "System is in safe state.\nSafe sequence is: ";
for (int i = 0; i < P ; i++)
cout << safeSeq[i] << " ";
cout << endl;
return true;
}
void resourceRequest(int processes[], int avail[], int maxm[][R], int allot[][R], int need[][R], int request[], int p)
{
int i = 0, j = 0;
for (; i < R; i++)
if (request[i] > need[p][i])
break;
if (i == R){
for (i = 0; i < R; i++)
if (request[i] > avail[i])
break;
if (i == R){
for (i = 0; i < R; i++){
avail[i] -= request[i];
allot[p][i] += request[i];
need[p][i] -= request[i];
}
if (isSafe(processes, avail, maxm, allot)){
//print allot need avail
cout << "Process\tAllocation\tMax\t\tNeed\t\tAvailable" << endl;
cout << "\tR1 R2 R3 \tR1 R2 R3\t R1 R2 R3\t R1 R2 R3" << endl;
cout << "0\t " << allot[0][0] << " " << allot[0][1] << " " << allot[0][2] << "\t " << maxm[0][0] << " " << maxm[0][1] << " " << maxm[0][2] << "\t " << need[0][0] << " " << need[0][1] << " " << need[0][2] << "\t " << avail[0] << " " << avail[1] << " " << avail[2] << "\n";
for (i = 1; i < P; i++){
cout << i << "\t " << allot[i][0] << " " << allot[i][1] << " " << allot[i][2] << "\t " << maxm[i][0] << " " << maxm[i][1] << " " << maxm[i][2] << "\t " << need[i][0] << " " << need[i][1] << " " << need[i][2] << endl;
}
}
else{
cout << "\nThe new state is unsafe, process must wait." << endl;
for (i = 0; i < R; i++){
avail[i] += request[i];
allot[p][i] += request[i];
need[p][i] -= request[i];
}
}
}
else{
cout << "Process " << p << " must wait, since the resources are not available." << endl;
}
}
else{
cout << "Process has exceeded its maximum claim." << endl;
}
}
int main()
{
int i = 0, j = 0;
int processes[] = {0, 1, 2, 3, 4};
cout << "Enter the available instances of resources: " << endl;
int avail[R];
cin >> avail[0] >> avail[1] >> avail[2];
cout << "Enter the maximum resource that can be allocated to processes: " << endl;
int maxm[P][R];
for(i = 0; i < P; i++){
cin >> maxm[i][0] >> maxm[i][1] >> maxm[i][2];
}
cout << "Enter the resources allocated to processes: " << endl;
int allot[P][R];
for(i = 0; i < P; i++){
cin >> allot[i][0] >> allot[i][1] >> allot[i][2];
}
int need[P][R];
for(i = 0; i < P; i++)
for(j = 0; j < R; j++)
need[i][j] = maxm[i][j] - allot[i][j];
if(isSafe(processes, avail, maxm, allot))
{
int need[P][R], request[R], p;
calculateNeed(need, maxm, allot);
cout << "Choose a process: " << endl;
cin >> p;
cout << "Enter the request for resources for process chosen: " << endl;
cin >> request[0] >> request[1] >> request[2];
resourceRequest(processes, avail, maxm, allot, need, request, p);
}
return 0;
}