recursive search mini project

[dylansanderson]

what is wrong with this code?
Here’s how we do it. Assume our array is already sorted. Imagine our array with indexes low​ to
high​. We’re searching for our target​ value. We will point to the midpoint index in the array.
array[]
low mid high
● If array[m] == target​, return that index. We’ve found it!
● If array[m] < target​, recursively search from index mid + 1​ to high​.
● If array[m] > target​, recursively search from index low​ to mid - 1​.


-------------------------(header file)-------------------------------------------

#pragma once

//This program will recursively search through arrays to find the target index

template <class T >
int binary_search(T array[], int low, int high, int T target) {
int midpointIndex;
midpointIndex = (low + high) / 2;

if (array[midpointIndex] == target) {

return array[midpointIndex];
}


if (array[midpointIndex] < target) {

return binary_search(array[], midpointIndex + 1, high, target);

}

if (array[midpointIndex] > target) {


return binary_search([midpointIndex], low, midpointIndex - 1, target);

}

}

-----------------------------------(main file)---------------------------

// Feel free to modify this file
// or create a header file and link it in.

#include"searchHeader.h"
#include <iostream>
using namespace std;

int main(int argc, char const *argv[])
{
int iList[6] = {1, 3, 5, 17, 23, 98};
// double dList[6] = {0.3, 1.2, 11.3, 17.1, 18.9, 97.6};
// char cList[6] = {'a', 'c', 'f', 'j', 'o', 'z'};

int iAns = binary_search(iList, 0, 5, 17);
// int dAns = binary_search(dList, 0, 5, 18.9);
// int cAns = binary_search(cList, 0, 5, 'c');

cout << "Integer answer at index " << iAns << endl;
// cout << "Double answer at index " << dAns << endl;
// cout << "Char answer at index " << cAns << endl;

return 0;
}
------------


main file is fine and should remain untouched. It is a project in school, teacher provides the main file. My problem is I dont know what goes in the arguments of return binary_search(.....)

[lastchance]

You have errors in several argument lists.

You also need to return the index, not the target value.

You fail to take any action if the target is NOT found. In the code below I have set the return index to -1 in this case (and you should check it with an appropriate test case in main().

#pragma once

//This program will recursively search through arrays to find the target index

template <class T > int binary_search( T array[], int low, int high, T target )  // <==== just T target
{
   if ( low > high ) return -1;        // <==== necessary if target NOT found

   int midpointIndex;
   midpointIndex = ( low + high ) / 2;

   if (array[midpointIndex] == target)
   {
      return midpointIndex;            // <==== return the index, not the value
   }
   else if ( array[midpointIndex] < target )
   {
      return binary_search( array, midpointIndex + 1, high, target );  // <==== argument just NAME of array
   }
   else
   {
      return binary_search( array, low, midpointIndex - 1, target );   // <==== ditto
   }
}