Modify the sequential search and binary search program below so that they use po

Question

Modify the sequential search and binary search program below so that they use pointer notation to access array elements. Do not use [ ] to retrieve an element of the array. Use * and / or & instead.

#include<iostream>
#include<fstream>

using namespace std;

void binsearch(int arr[], int x)
{
int l = 0;
int r = 9;
int count = 0;
while (l <= r)
{
    int m = l + (r-l)/2;
    if (arr[m] == x)
        count++;
    if (arr[m] < x)
        l = m + 1;
    else
         r = m - 1;
}
cout << x << " appeared " << x << " times ";
}

int main(){

    ifstream fin("unsortedNumbers.txt");
    ofstream fout("sortedNumbers.txt");
    int data[10];
    int temp;
    int n;

    if (!fin) {
        cout << "Error in opening file ";
        return 0;
    }
    for (int i = 0; i<10; i++){
       fin >> data[i];
    }
    fin.close();
    for (int i = 0; i<10; i++){
       for(int j=i+1; j<10; j++){
          if (data[i] > data[j]){
            temp = data[i];
            data[i] = data[j];
            data[j] = temp;
          }
       }
    }
    for (int i = 0; i<10; i++){
       fout << data[i] << " ";
    }   
    fout << endl;
    fout.close();
    cout << "Minimum :" << data[0] << endl;
    cout << "Maximum :" << data[9] << endl;

    cout << "Enter the number to search : " ;
    cin >> n;
    binsearch(data,n);
    return 0;
}

Explanation / Answer

To convert from index based accessing to pointer based:

arr[m] becomes *(arr+m)

The rest of the code will remain the same.

arr is the starting position of the array. (arr+m) is arr[0+m] i.e arr[m]

I hope its clear. :)

*****************************************************************************************************

#include<iostream>
#include<fstream>

using namespace std;

void binsearch(int arr[], int x)
{
int l = 0;
int r = 9;
int count = 0;
while (l <= r)
{
    int m = l + (r-l)/2;
    if (*(arr+m) == x)
        count++;
    if (*(arr+m) < x)
        l = m + 1;
    else
         r = m - 1;
}
cout << x << " appeared " << x << " times ";
}

int main(){

    ifstream fin("unsortedNumbers.txt");
    ofstream fout("sortedNumbers.txt");
    int data[10];
    int temp;
    int n;

    if (!fin) {
        cout << "Error in opening file ";
        return 0;
    }
    for (int i = 0; i<10; i++){
       fin >> *(data+i);
    }
    fin.close();
    for (int i = 0; i<10; i++){
       for(int j=i+1; j<10; j++){
          if ( *(data+i) > *(data+j) ){
            temp = *(data+i);
            *(data+i) = *(data+j);
           *(data+j) = temp;
          }
       }
    }
    for (int i = 0; i<10; i++){
       fout << *(data+i) << " ";
    }
    fout << endl;
    fout.close();
    cout << "Minimum :" << *(data+0) << endl;
    cout << "Maximum :" << *(data+9) << endl;

    cout << "Enter the number to search : " ;
    cin >> n;
    binsearch(data,n);
    return 0;
}

*************************************************************************************************************

Output screens:

I hope this helps you.
If you find my answer helpful,
Kindly rate the answer.
All the best :)

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