c++ program to implement preemitive Priority based scheduling algorithm using function.

#include <iostream>
#include<fstream>
using namespace std;
void writeFile(char fname[],int n)
{    fstream fwrite;
    fwrite.open(fname,ios::out);
    float a,b,p;
    for(int  i=0;i<n;i++)
    {    cout<<"enter arival time :";
        cin>>a;
        cout<<endl<<"enter brust time:";
        cin>>b;
        cout<<endl<<"enter prority time:";
        cin>>p;





       fwrite<<i<<endl<<a<<endl<<b<<endl<<p<<endl;
    }   
    fwrite.close();
}
void readFile(char fname[],int n)
{    fstream fread;
    fread.open(fname,ios::in);
    float total,wait[n];
    float p[n],twaiting=0,waiting=0;
    int proc;
    int stack[n];
    float brust[n],arrival[n],sbrust,temp[n],top=n,prority[n];
    int i;
    for( i=0;i<n;i++)
    {    stack[i]=i;
        fread>>p[i]>>arrival[i]>>brust[i]>>prority[i];
        temp[i]=arrival[i];
        sbrust=brust[i]+sbrust;
    }
    fread.close();
    for(i=0;i<sbrust;i++)
    {    proc=stack[0];
        if(temp[proc]==i)
            twaiting=0;
        else
            twaiting=i-(temp[proc]);
        temp[proc]=i+1;   
               
        wait[proc]=wait[proc]+twaiting;
        waiting=waiting+(twaiting);
        brust[proc]=brust[proc]-1;
       
        if(brust[proc]==0)
        {
            for(int x=0;x<top-1;x++)
            {
                stack[x]=stack[x+1];
               
            }
            top=top-1;
      }
        for(int z=0;z<top-1;z++)
        {   
            if((prority[stack[0]]>prority[stack[z+1]]) && (arrival[stack[z+1]] <= i+1))
            {
                int t=stack[0];
                stack[0]=stack[z+1];
                stack[z+1]=t;
            }
        }
       
       
    }
    cout<<"waiting:"<<waiting;
    float tu=(sbrust+waiting)/n;
   cout<<endl<<"Average turnaround time is:"<<tu;
 
}
int main()
{   
    int n;
    char fname[100];
    cout<<"enter your toal no. of process";
    cin>>n;
    cout<<"enter your file name";
    cin>>fname;
    writeFile(fname,n);   
    readFile(fname,n);
   
   
return 0;
}

Various Process Scheduling Algorithms:

• First come First served Scheduling Algorithm
• Non preemptive Shortest job first (SJF) scheduling Algorithm
• preemptive shortest job first (SJF) scheduling algorithm
• Non preemptive priority scheduling algorithm
• preemptive priority scheduling algorithm
• Roun Robin scheduling Algorithm

Various Page Replacement Algorithms:

• Page replacement using Least Recently Used (LRU) algorithm techneques.
• Page replacement using First come first served algorithm techniques.

Various Disk Head Movement Counting Algorithms:

• Count the disk head movement using first come first served (FCFS) algorithm
• head movement count using shortest seek job first (SSJF)
• head movement count using scan scheduling algorithm
• head movement count using c-scan scheduling algorithm
• head movement count using loop scheduling algorithm
• head movement count using c-loop scheduling alogrithm