Question

Add binary_search() (page 462) to your program. Modify main() to prompt the user for a number to search (until ^D) and display the position of the number in the sorted vector. Try your program for the following user input:

1 15 18 40 30 50 ^D

The output should be:

-1 2 -1 7 5 -1

int binary_search(vector<int> v, int from, int to, int value)
{
if (from > to)
return -1;
int mid = (from + to) / 2;
if (v[mid] == value)
return mid;
else if (v[mid] < value)
return binary_search(v, mid + 1, to, value);
else
return binary_search(v, from, mid - 1, value);
}

#include<iostream>
#include<fstream>
#include<vector>
using namespace std;
//selection sort function prototype
void selectionSort(vector<int>&v);
//Main method
int main()
{
   //file read object
   ifstream file;
   //vector declaration
   vector<int>numbers;
   //name of the filr given the object to open
   file.open("sort.txt");
   //file is not found error
   if (!file) {
       cout << "File not found" << endl;
       return 0;
   }
   //Other wise read file data and store in a vector
   else {
       while (!file.eof()) {
           int line;
           if (file >> line){
               numbers.push_back(line);
           }

       }
       //Vector values before sort
       cout << "Before sorting:" << endl;
       for (int i = 0; i < numbers.size(); i++) {
           cout << numbers[i] << " ";
       }

       cout << endl;
   }
   //call sort function
   selectionSort(numbers);
   cout << "After sorting:" << endl;
   //Vector values after sort
   for (int i = 0; i < numbers.size(); i++) {
       cout << numbers[i] << " ";
   }

   cout << endl;

    return 0;
}
//Selection sort implementation
void selectionSort(vector<int> &v) {
   int vecsize = v.size();
   for (int i = 0; i < vecsize-1; i++)
       for (int j = i + 1; j < vecsize; j++)
           if (v[i] > v[j])
               swap(v[i], v[j]);
}

Answer 1

PLASE GIVE THUMBS UP, THANKS, FOR ANY QUERY LEAVE COMMENT.

AS YOUR sort.txt file is not given in question so i can't execute according to your input because it will not give that exact location.

i create my own list and input. you can check on your given sort.txt it will work 100% smooth

SAMPLE OUTPUT:

CODE :

#include<iostream>
#include<fstream>
#include<vector>
#include <cstdlib>
using namespace std;
//selection sort function prototype
void selectionSort(vector<int>&v);
int binary_search(vector<int> v, int from, int to, int value);
//Main method
int main()
{
//file read object
ifstream file;
//vector declaration
vector<int>numbers;
//name of the filr given the object to open
file.open("sort.txt");
//file is not found error
if (!file) {
cout << "File not found" << endl;
return 0;
}
//Other wise read file data and store in a vector
else {
while (!file.eof()) {
int line;
if (file >> line){
numbers.push_back(line);
}
}
//Vector values before sort
cout << "Before sorting:" << endl;
for (int i = 0; i < numbers.size(); i++) {
cout << numbers[i] << " ";
}
cout << endl;
}
//call sort function
selectionSort(numbers);
cout << "After sorting:" << endl;
//Vector values after sort
for (int i = 0; i < numbers.size(); i++) {
cout << numbers[i] << " ";
}
cout << endl;
int value;
while(1)
{
    cout<<"Enter number to search : ";
    if(cin>>value){
   }
    else
    break;
    cout<<binary_search(numbers,0,numbers.size()-1,value)<<endl;
}
return 0;
}
//Selection sort implementation
void selectionSort(vector<int> &v) {
int vecsize = v.size();
for (int i = 0; i < vecsize-1; i++)
for (int j = i + 1; j < vecsize; j++)
if (v[i] > v[j])
swap(v[i], v[j]);
}

int binary_search(vector<int> v, int from, int to, int value)
{
if (from > to)
return -1;
int mid = (from + to) / 2;
if (v[mid] == value)
return mid;
else if (v[mid] < value)
return binary_search(v, mid + 1, to, value);
else
return binary_search(v, from, mid - 1, value);
}