Program for First Fit  , Worst Fit , Best Fit Memory Allocation Algorithm

  

C++  Program for Best fit Algorithm

 

#include<iostream>

using namespace std;

int main()

{

    int fragment[20],b[20],p[20],i,j,nb,np,temp,lowest=9999;

    static int barray[20],parray[20];

    cout<<"\n\t\t\tMemory Management Scheme - Best Fit";

    cout<<"\nEnter the number of blocks:";

    cin>>nb;

    cout<<"Enter the number of processes:";

    cin>>np;

    

    cout<<"\nEnter the size of the blocks:-\n";

    for(i=1;i<=nb;i++)

    {

        cout<<"Block no."<<i<<":";

        cin>>b[i];

    }

    

    cout<<"\nEnter the size of the processes :-\n";

    for(i=1;i<=np;i++)

    {

        cout<<"Process no. "<<i<<":";

        cin>>p[i];

    }

    

    for(i=1;i<=np;i++)

    {

        for(j=1;j<=nb;j++)

        {

            if(barray[j]!=1)

            {

                temp=b[j]-p[i];

                if(temp>=0)

                    if(lowest>temp)

                    {

                        parray[i]=j;

                        lowest=temp;

                    }

            }

        }

        

        fragment[i]=lowest;

        barray[parray[i]]=1;

        lowest=10000;

    }

    

    cout<<"\nProcess_no\tProcess_size\tBlock_no\tBlock_size\tFragment";

    for(i=1;i<=np && parray[i]!=0;i++)

        cout<<"\n"<<i<<"\t\t"<<p[i]<<"\t\t"<<parray[i]<<"\t\t"<<b[parray[i]]<<"\t\t" <<fragment[i];

    

    return 0;

}

 

OUTPUT :

Out put for Best fit Memory Allocation Algorithm

C++  Program for First fit algorithm

#include<iostream>

using namespace std;

int main()

{

    int bsize[10], psize[10], bno, pno, flags[10], allocation[10], i, j;

    for(i = 0; i < 10; i++)

    {

        flags[i] = 0;

        allocation[i] = -1;

    }

    

    cout<<"Enter no. of blocks: ";

    cin>>bno;

    

    cout<<"\nEnter size of each block: ";

    for(i = 0; i < bno; i++)

        cin>>bsize[i];

    cout<<"\nEnter no. of processes: ";

    cin>>pno;

    

    cout<<"\nEnter size of each process: ";

    for(i = 0; i < pno; i++)

        cin>>psize[i];

    for(i = 0; i < pno; i++)         //allocation as per first fit

        for(j = 0; j < bno; j++)

            if(flags[j] == 0 && bsize[j] >= psize[i])

            {

                allocation[j] = i;

                flags[j] = 1;

                break;

            }

    

    //display allocation details

    cout<<"\nBlock no.\tsize\t\tprocess no.\t\tsize";

    for(i = 0; i < bno; i++)

    {

        cout<<"\n"<< i+1<<"\t\t"<<bsize[i]<<"\t\t";

        if(flags[i] == 1)

            cout<<allocation[i]+1<<"\t\t\t"<<psize[allocation[i]];

        else

            cout<<"Not allocated";

    }

    

    return 0;

} 

OUTPUT :

Out put for First fit Memory Allocation Algorithm

C++  Program for Worst fit Algorithm

#include <iostream>

 

using namespace std;

 

int main()

{

    int nBlocks,nProcess,blockSize[20],processSize[20];

     

    cout<<" Enter the number of blocks: "; cin>>nBlocks;

    cout<<" Enter the number of processes: "; cin>>nProcess;

     

    cout<<" Enter the size of "<<nBlocks<<" blocks: ";

    for(int i=0;i<nBlocks;i++) cin>>blockSize[i];

       

    cout<<" Enter the size of "<<nProcess<<" processes: ";

    for(int i=0;i<nProcess;i++) cin>>processSize[i];

     

      

      for(int i=0;i<nProcess;i++)

       {

           int max = blockSize[0];

           int pos = 0;

           

           for(int j=0;j<nBlocks;j++)

            if(max < blockSize[j]) { max = blockSize[j]; pos = j; } if(max >= processSize[i])

            {

                cout<<"\nProcess "<<i+1<<" is allocated to block "<<pos+1;

                blockSize[pos] = blockSize[pos]-processSize[i];

            }

            else{

            cout<<"\nProcess "<<i+1<<" can't be allocated";

                

            }

       }

     return 0;

}

 

OUTPUT :

Out put for Worst fit Memory Allocation Algorithm