Question

2019/Midterm

At Unknown University, the Admissions department has discovered that the best applicants usually go to bigname

schools instead and the worst often do poorly in courses, so the school wants to concentrate recruitment

efforts and financial aid resources on the middle half of the applicants. You must write a c++ program that takes a

file containing a list of applicants, in which each applicant has a total SAT score, and prints a list of the middle

half of these applicants. (Eliminate the best quarter and the worst quarter). This can be done using a simple

iterative technique. First, read the data from a file named apply.txt into an array of integers (let N be the total

number of applicants). This begin a loop that eliminates applicants one at a time, until only half are left. Within

this loop, let first be a pointer to the first array element that is still included, last be a pointer to the last one,

and r (the number of remaining) be initialized to N. Each time around the loop, either first is incremented or last

is decremented and r decreases by 1. At each step,

a. If r is even, find the remaining applicant with the lowest SAT score and swap it with the applicant at

first. Then increment first, decrement r, and repeat.

b. If r is odd, find the remaining applicant with the highest SAT score and swap it with the applicant at last.

Then decrement last and r and repeat.

c. Quit when r <= N/2. Return the values of first and r.

When only half the applicants are left, write the sorted list to a user-specified output file.

Answer 1

#include<iostream>
#include<fstream>
#include<string>
using namespace std;
int main()
{
   int n = 0;
int first,last,temp;
int arr[100],a[100];
string filename;
ifstream File;
File.open("apply.txt");
while(!File.eof())
{
File>>arr[n];
n++;
}
File.close();
   int r=n;
first=0;
last=n-1;
while(r>n/2)
{
   if(r%2==0)
   {
       int small=arr[0];
       for(int i=1;i<n;i++)
       {
           if(small>arr[i])
           small=i;
           }
           temp=arr[small];
           arr[small]=arr[first];
           arr[first]=temp;
           ++first;
           --r;
       }
       else
       {
           int large=arr[0];
       for(int i=1;i<n;i++)
       {
           if(large<arr[i])
           large=i;
           }
           temp=arr[large];
           arr[large]=arr[last];
           arr[last]=temp;
           --last;
           --r;
       }
   }
   for(int i=first;i<last;i++)
   {
       for(int j=i+1;j<last;j++)
       {
           if(arr[j]<arr[i])
           {
               temp=arr[j];
               arr[j]=arr[i];
               arr[i]=temp;
           }
       }
   }
   ofstream outputfile;
   cout<<"Enter the name of the output file: ";
   getline(cin,filename);
outputfile.open(filename.c_str());
   for(int i=first;i<last;i++)
   {
       outputfile<<arr[i]<<"\n";
   }
outputfile.close();
n=0;
ifstream File1;
File1.open(filename.c_str());
cout<<"The output file contains: ";
while(!File1.eof())
{
File1>>a[n];
n++;
}
for(int i=0;i<n-1;i++)
   {
       cout<<"\n"<<a[i]<<" ";
   }
   File1.close();
return 0;
}