binary search not returning value

[firescorpian99]

I am writing a code to find a user input value in a randomly generated array. I am not getting any values to be found. As far as i can tell the rest of my code is working ok. I inserted a line to show the array elements before the user input. I've been looking at this for two days now and am just as stumped now as i was before. Help is appreciated!

Thanks!


#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;

void CreateArray(int [], int);
void BubbleSort(int [], int);
int BinarySearch(const int [], int, int);
void Swap(int &, int &);

int main ()
{
const int SIZE = 20;
int RandArray[SIZE];
int input, results, index = 0;
char choice;
int *ptr = nullptr;


CreateArray(RandArray, SIZE); // create random number array

BubbleSort(RandArray, SIZE); // sort random array

while (index < SIZE)
{
cout << RandArray[index] << endl;
index++;

}

do
{
cout << "Please enter a number between 1 and 100" << endl;
cin >> input;
while (input < 1 || input > 100)
{
cout << "please enter a different number that meets the requirements." << endl;
cin >> input;
}

results = BinarySearch(RandArray, SIZE, input); // search for user input

if (results == -1)
cout << "Your number is not in the array" << endl;
else
{
ptr = &results;
cout << "Your number is in the array at position " << ptr << endl;
}

cout << results << endl;

cout << "Do you want to try another number? Enter Y or N" << endl;
cin >> choice;

}
while (toupper(choice) == 'Y');

cout << "End of line" << endl;

return 0;

}


void CreateArray(int array[], int size)
{
unsigned seed = time(0); // get system time
srand(seed); // seed random generator
const int MIN_VALUE = 1, MAX_VALUE = 100, ARRAY_SIZE = 20;



for (int index = 0; ARRAY_SIZE > index; index++) // create array
array[index] = (rand() % (MAX_VALUE - MIN_VALUE + 1)) + MIN_VALUE;

for(int i = 0; i < size; i++) //find and change duplicates
{
for(int j = i; j < size; j++)
{
if (array[i] == array[j])
{
array[j] = array[j] - 1;
}
}
}
}


void BubbleSort(int array[], int size)
{
int maxElement;
int index;

for (maxElement = size - 1; maxElement > 0; maxElement--)
{
for (index = 0; index < maxElement; index++)
{
if (array[index] < array[index + 1])
{
swap(array[index], array[index+1]);
}
}
}
}


int BinarySearch(const int array[], int size, int value)
{
int first = 0, last = size - 1, middle, position = -1;
bool present = false;


while (!present && first <= last)
{
middle = (first + last) / 2; // find middle number
if (array[middle] == value) // if value is middle element
{
present = true;
position = middle;
}
else if (array[middle] > value) // if value is in lower half
last = middle - 1;
else
first = middle + 1; // if value is in upper half
}

return position;

}




void Swap(int &a, int &b)
{
int temp = a;
a = b;
b = temp;
}

[Manga]

If I understand correctly, you want to see if user can guess one of the randomly generated numbers?

To find a match you must compare the user input to each element of the array.

Maybe like this...

int BinarySearch(const int array[], int size, int value)
 {
 int  position = -1;



 for (int i = 0;  i < size; i++) {
     if(array[i] == value) {
         position = i;
         break;
     }
 }

 return position;

 }

[firescorpian99]

yes, that works! Im not sure what my code was trying to do then. Thanks!

[RobertGreene]

Hi everyone,I go through all the iteration that you have been mentioned about.I recommended that you must focus on the loop iteration with all int values.Thanks