banker's algorithm in c++ - c++

Question

I have project in banker algorithm implement in c++
But I have small mistake :') in resource request
I didn't know what the mistake. The first if statement doesn't work :(
#include<iostream>
#include<vector>
using namespace std;
int main() {
int work[4];
int allocation[5][4];
int max[5][4];
int need[5][4];
int p, pr, r, a, aval[4], req[4];
bool state[5], test;
vector < int > avl;
//----------------------------------------
test = true;
for (int i = 0; i < 4; i++)
work[i] = aval[i];
for (int i = 0; i < 5; i++)
state[i] = false;
//----------------------------enter p r---------------------------------
cout << "Enter the number of processes in the system :";
cin >> p;
cout << "\nEnter the number of recourses :";
cin >> r;
//---------------------enter alloc---
cout << "\nEnter the allocation " << endl;
if (r = 1)
{
cout << "\t A \n \t ";
}
else if (r = 2)
{
cout << "\t A B \n \t ";
}
else if (r = 3)
{
cout << " A B C\n \t ";
}
else if (r = 4)
{
cout << " A B C D\n \t ";
}
for (int i = 0; i < p; i++)
{
cout << endl << "\t" << "P" << i << ":";
for (int j = 0; j < 4; j++)
{
cin >> allocation[i][j];
cout << " ";
}
}
//-----------------------------entet max----------------
cout << "\nEnter the MAX" << endl;
if (r = 1)
cout << " A \n \t ";
else if (r = 2)
cout << " A B \n \t ";
else if (r = 3)
cout << " A B C\n \t ";
else if (r = 4)
cout << " A B C D\n \t ";
for (int i = 0; i < p; i++)
{
cout << endl << "P" << i << ":";
for (int j = 0; j < 4; j++)
{
cin >> max[i][j];
need[i][j] = max[i][j] - allocation[i][j];
}
}
//-----------------enter ava--------------
cout << "\nEnter the avaliable number : " << endl;
for (int i = 0; i < 4; i++)
{
cin >> aval[i];
cout << " ";
}
//-----------------enter request--------------
cout << "\nEnter the number of process want be request : ";
cin >> pr;
cout << "\nEnter the request number : " << endl;
for (int i = 0; i < 4; i++)
{
cin >> req[i];
cout << " ";
}
//-----------------------------------COUT---------------------
cout << endl << "There are " << p << " processes in the system." << endl << endl;
cout << "There are " << r << " resource types." << endl << endl;
//----------------------------------cout allocation---------------
cout << " The allocation Matrix : " << endl << endl;
cout << "\t A B C D";
for (int i = 0; i < p; i++)
{
cout << endl << "\tP" << i << ":";
for (int j = 0; j < 4; j++)
{
cout << allocation[i][j] << " ";
}
cout << endl;
}
//----------------------------------cout max---------------
cout << endl << " The Max Matrix is... " << endl << endl;
cout << "\t A B C D";
for (int i = 0; i < p; i++)
{
cout << endl << "\tP" << i << ":";
for (int j = 0; j < 4; j++)
{
cout << max[i][j] << " ";
}
cout << endl;
}
//-------------------------cout need-------------------------------------------
cout << endl << " The Need Matrix is... " << endl << endl;
cout << "\t A B C D";
for (int i = 0; i < p; i++)
{
cout << endl << "\tP" << i << ":";
for (int j = 0; j < 4; j++)
{
cout << need[i][j] << " ";
}
cout << endl;
}
//----------------------------- cout aval ---------------------
cout << endl << "The Available Vector is..." << endl << endl;
cout << "A B C D" << endl;
for (int i = 0; i < 4; i++)
{
cout << aval[i] << " ";
}
//-----------------------------------SAFE STATE-----------------------
int k = 0;
for (k = 0; k < p; k++) {
if (state[k] == false) {
test = false;
for (int j = 0; j<r; j++) {
if (need[k][j] > work[j])
break;
if (need[k][j] <= aval[j])
test = true;
}
}
}
if (test == true) {
for (int j = 0; j < r; j++)
{
work[j] = work[j] + allocation[k][j];
}
state[k] = true;
cout << endl << endl << "THE SYSTEM IS IN A SAFESTATE!" << endl;
}
if (test == false) {
state[k] = false;
cout << endl << endl << "THE SYSTEM IS NOT IN A SAFE STATE!";
}
//-----------------------------------request------------------------
cout << "\nThe Request Vector is..." << endl;
cout << " A B C D" << endl;
cout << pr << ":";
for (int i = 0; i < 4; i++)
{
cout << req[i] << " ";
}
bool test2 = false;
for (int i = 0; i < p; i++) {
if (pr == p) {
for (int j = 0; j < 4; j++)
{
if (req[j] <= avl[j] && req[j] <= need[i][j])
{
test2 = true;
}
else
{
break;
}
}
if (test2 = true)
{
for (int n = 0; n < r; n++)
{
aval[n] = aval[n] - req[n];
allocation[i][n] = allocation[i][n] + req[n];
need[i][n] = need[i][n] - req[n];
}
cout << "THE REQUEST CAN BE GRANTED!" << endl << endl;
cout << "The Available Vector is...";
cout << "A B C D" << endl;
for (int x = 0; x < r; x++)
{
cout << aval[x] << " ";
}
}
else
{
cout << "THE REQUEST CANNOT BE GRANTED!" << endl << endl;
}
}
}
//------------------------------------------------------------------------------
system("pause");
return 0;
}

Answer 1

When checking if two primitive types are equal, you need to use "==" instead of "="
e.g, change your if statements from
if ( r = 1 )
to
if (r == 1)

Answer 2

Apart from above
work[i] = aval[i]; - aval[i] - has not been initialised
Read up on switch instead of r == 1 do this etc. ( I took into account the above statement and the chained if statements
Ditto with = true. Learn the difference between comparison and assignment
Perhaps learn how to use the debugger
You need to use cout << flush so that the output is sent.
.... I could add others - this is enough to get on with

Answer 3

Here is the whole working program. I made some changes in it and made the code more easy to understand.
int p, r;
bool test;
vector < int > avl;
//----------------------------enter p r---------------------------------
system("clear");
cout << "Enter the number of processes in the system: ";
cin >> p;
cout << "Enter the number of recourses: ";
cin >> r;
//test
int allocation[p][r];
int max[p][r];
int need[p][r];
int aval[r];
int state[p];
test = true;
//test
//---------------------enter alloc---
system("clear");
cout << "\nEnter the allocation " << endl;
if (r == 1)
{
cout << "\t A \n \t ";
}
else if (r == 2)
{
cout << "\t A B \n \t ";
}
else if (r == 3)
{
cout << "\t A B C \n \t ";
}
else if (r == 4)
{
cout << "\t A B C D \n \t ";
}
for (int i = 0; i < p; i++)
{
cout << endl << "\t" << "P" << i << ": ";
for (int j = 0; j < r; j++)
{
cin >> allocation[i][j];
cout << " ";
}
}
system("clear");
//-----------------------------entet max----------------
cout << "\nEnter the MAX" << endl;
if (r == 1)
cout << "\t A \n \t ";
else if (r == 2)
cout << "\t A B \n \t ";
else if (r == 3)
cout << "\t A B C\n \t ";
else if (r == 4)
cout << "\t A B C D\n \t ";
for (int i = 0; i < p; i++)
{
cout << endl << "\t" << "P" << i << ": ";
for (int j = 0; j < r; j++)
{
cin >> max[i][j];
need[i][j] = max[i][j] - allocation[i][j];
}
}
system("clear");
//-----------------enter ava--------------
cout << "\nEnter the avaliable number : " << endl;
cout<<"\tAvail: ";
for (int i = 0; i < r; i++)
{
cin >> aval[i];
cout << " ";
}
//-----------------------------------COUT---------------------
system("clear");
system("clear");
cout << "There are " << p << " processes in the system." << endl;
cout << "There are " << r << " resource types." << endl << endl;
//----------------------------------cout allocation---------------
cout << " The allocation Matrix : " << endl << endl;
if (r == 1)
cout << "\t A \n \t ";
else if (r == 2)
cout << "\t A B \n \t ";
else if (r == 3)
cout << "\t A B C\n \t ";
else if (r == 4)
cout << "\t A B C D\n \t ";
for (int i = 0; i < p; i++)
{
cout << endl << "\tP" << i << ": ";
for (int j = 0; j < r; j++)
{
cout << allocation[i][j] << " ";
}
cout << endl;
}
//----------------------------------cout max---------------
cout << endl << " The Max Matrix is... " << endl << endl;
if (r == 1)
cout << "\t A \n \t ";
else if (r == 2)
cout << "\t A B \n \t ";
else if (r == 3)
cout << "\t A B C\n \t ";
else if (r == 4)
cout << "\t A B C D\n \t ";
for (int i = 0; i < p; i++)
{
cout << endl << "\tP" << i << ": ";
for (int j = 0; j < r; j++)
{
cout << max[i][j] << " ";
}
cout << endl;
}
//-------------------------cout need-------------------------------------------
cout << endl << " The Need Matrix is... " << endl << endl;
for(int i = 0; i < p; i++)
{
for(int j = 0; j < r; j++)
{
need[i][j] = max[i][j] - allocation[i][j];
}
}
if (r == 1)
cout << "\t A \n \t ";
else if (r == 2)
cout << "\t A B \n \t ";
else if (r == 3)
cout << "\t A B C\n \t ";
else if (r == 4)
cout << "\t A B C D\n \t ";
for (int i = 0; i < p; i++)
{
cout << endl << "\tP" << i << ": ";
for (int j = 0; j < r; j++)
{
cout << need[i][j] << " ";
}
cout << endl;
}
//----------------------------- cout aval ---------------------
cout << endl << "The Available Vector is..." << endl << endl;
cout<<"\tAvail: ";
for (int i = 0; i < r; i++)
{
cout << aval[i] << " ";
}
cout<<endl;
//--------SAFESTATE----------SAFESTATE----------SAFESTATE-------------------
int count = p;
cout<<endl;
cout<<"Safe sequence: ";
do{
for(int loop_var = 0; loop_var < p; loop_var++)
{
test = false;
for (int j = 0; j < r; j++) {
if(state[loop_var] == true)
{
break;
}
if(need[loop_var][j] > aval[j])
{
test = false;
state[loop_var] = false;
break;
}
else
{
test = true;
}
}
if((test))
{
count--;
state[loop_var] = true;
for(int sb = 0; sb < r; sb++)
{
aval[sb] = aval[sb] + allocation[loop_var][sb];
}
if(count == 0)
{
cout<<"P"<<loop_var<<" ";
}
else if(count > 0)
{
cout<<"P"<<loop_var<<"-->";
}
}
}
}while(count != 0);
cout<<endl;
//--------SAFESTATE----------SAFESTATE----------SAFESTATE-------------------
cout<<endl;
cout<<"The new available vector is: ";
for(int i = 0; i < r; i++)
{
cout<<aval[i]<<" ";
}
cout << endl << endl;
return 0;