I am trying to change the code from searches that return an array position to searches that count the number of comparisons. What should I return from the linear search? What is keeping the program from calling or completing the second binary search?

/*Ch8Ex8

June Stine

This program performs a linear search and a binary search on an array with 20 values.

Each search tracks and displays the number of comparisons made and the results.

*/

#include <iostream>

using namespace std;

//Function prototype

void searchList(const int[], const int, int);

int binarySearch(const int[], const int, int);

const int ARRAY_SIZE = 20;

int main()

{

const int tests[ARRAY_SIZE] = { 101,142,147,189,199,207,222,234,289,296,310,

319,388,394,417,429,447,521,536,600 };

int number;

//Print my name as the first line of output.

cout << "June Stine" << endl;

//Prompt the user to enter a number to search for.

cout << "Enter the number you are looking for: "<< endl;

cin >> number;

//Validate the number entered.

while (number <= 100 && number > 600)

{

cout << "That number is not within the range of tests. Please enter a number between 100 and 600." << endl;

cin >> number;

}

//Perform a linear search on the array for the number.

searchList(tests, ARRAY_SIZE, number);

bool found = false;

//Perform a binary search on the array for the number.

binarySearch(tests, ARRAY_SIZE, number);

//Keep the console window open until the enter key is pressed.

cout << "Press the enter key to exit.";

cin.ignore(cin.rdbuf()->in_avail() + 1);

return 0;

}

//Function Definition to perform a linear search for the user number.

void searchList(const int tests[], const int AARAY_SIZE, int number)

{

int count = 0;//Initialize variable for reporting the number of comparisons.

bool found = false;//Initialize the flag to indicate the number is not yet found.

while (count < (AARAY_SIZE - 1) && !found)//Define conditions for running the if comparison.

{

if (tests[count] == number)//Compare each array element with the the user number.

{

found = true;//Set flag to show the number was found.

//Display the results of search.

cout << "After " << (count + 1) << " comparisons, The linear search found number " << number << "." << endl;

}

count++;//Increment the count for each comparison.

}

//Report the number of comparisons when number is not found.

if (found == false)

cout << "After " << (count + 1) << " comparisons, the linear search did not find number " << number << "." << endl;

}

//Function Definition to perform a binary search for the user number.

int binarySearch(const int tests[], const int AARAY_SIZE, int number)

{

int first = 0, last = (ARRAY_SIZE - 1), middle;//Define variables to limit the range of the array size to search.

bool found = false;//Set the flag to show the number is not yet found.

int comparisons= 0;//Initialize a variable for the accumulating the number of comparisons.

while (!found && first <= last);//Set the conditions for continuing the binary search.

{

middle = (first + last) / 2.0;//Calculate the middle of the array.

if (tests[middle] == number)//Compare the middle element with the user number.

found = true;//Set the flag when the number is found.

else if (tests[middle] > number)//Set conditions for changing the value of the last element to search.

last = middle - 1;

else//Set conditions for changing the value of the first element to search.

first = middle + 1;

comparisons++;//Increment the accumulator for each comparison.

}

//Display the results for the search.

if (found = true)

cout << "After " << comparisons << "comparisons, the binary search found the number " << number << "." << endl;

else

cout << "After " << comparisons << "comparisons, The binary search did not find the number " << number << "." << endl;

return comparisons;

}

[Enter the number you are looking for:

521

After 18 comparisons, The linear search found number 521.

/code]

/*Ch8Ex8

June Stine

This program performs a linear search and a binary search on an array with 20 values.

Each search tracks and displays the number of comparisons made and the results.

*/

#include <iostream>

using namespace std;

//Function prototype

void searchList(const int[], const int, int);

int binarySearch(const int[], const int, int);

const int ARRAY_SIZE = 20;

int main()

{

const int tests[ARRAY_SIZE] = { 101,142,147,189,199,207,222,234,289,296,310,

319,388,394,417,429,447,521,536,600 };

int number;

//Print my name as the first line of output.

cout << "June Stine" << endl;

//Prompt the user to enter a number to search for.

cout << "Enter the number you are looking for: "<< endl;

cin >> number;

//Validate the number entered.

while (number <= 100 && number > 600)

{

cout << "That number is not within the range of tests. Please enter a number between 100 and 600." << endl;

cin >> number;

}

//Perform a linear search on the array for the number.

searchList(tests, ARRAY_SIZE, number);

bool found = false;

//Perform a binary search on the array for the number.

binarySearch(tests, ARRAY_SIZE, number);

//Keep the console window open until the enter key is pressed.

cout << "Press the enter key to exit.";

cin.ignore(cin.rdbuf()->in_avail() + 1);

return 0;

}

//Function Definition to perform a linear search for the user number.

void searchList(const int tests[], const int AARAY_SIZE, int number)

{

int count = 0;//Initialize variable for reporting the number of comparisons.

bool found = false;//Initialize the flag to indicate the number is not yet found.

while (count < (AARAY_SIZE - 1) && !found)//Define conditions for running the if comparison.

{

if (tests[count] == number)//Compare each array element with the the user number.

{

found = true;//Set flag to show the number was found.

//Display the results of search.

cout << "After " << (count + 1) << " comparisons, The linear search found number " << number << "." << endl;

}

count++;//Increment the count for each comparison.

}

//Report the number of comparisons when number is not found.

if (found == false)

cout << "After " << (count + 1) << " comparisons, the linear search did not find number " << number << "." << endl;

}

//Function Definition to perform a binary search for the user number.

int binarySearch(const int tests[], const int AARAY_SIZE, int number)

{

int first = 0, last = (ARRAY_SIZE - 1), middle;//Define variables to limit the range of the array size to search.

bool found = false;//Set the flag to show the number is not yet found.

int comparisons= 0;//Initialize a variable for the accumulating the number of comparisons.

while (!found && first <= last);//Set the conditions for continuing the binary search.

{

middle = (first + last) / 2.0;//Calculate the middle of the array.

if (tests[middle] == number)//Compare the middle element with the user number.

found = true;//Set the flag when the number is found.

else if (tests[middle] > number)//Set conditions for changing the value of the last element to search.

last = middle - 1;

else//Set conditions for changing the value of the first element to search.

first = middle + 1;

comparisons++;//Increment the accumulator for each comparison.

}

//Display the results for the search.

if (found = true)

cout << "After " << comparisons << "comparisons, the binary search found the number " << number << "." << endl;

else

cout << "After " << comparisons << "comparisons, The binary search did not find the number " << number << "." << endl;

return comparisons;

}

[Enter the number you are looking for:

521

After 18 comparisons, The linear search found number 521.

/code]

linear search is pretty simple: for(blah) did you find it? If yes, you looked #for loop variable# number of times (possibly off by one depending but you can figure it out and correct it). If you don't find it, it should have looked N times where N is number of things in the list. 18 looks correct to me for 521.

I don't see the issue with the binary search yet. Remember that you must sort a list to binary search it, else it will fail, and IMHO the effort to sort counts against the search, at least for the first one. If you search the list a bunch, the sort effort goes to zero the more searches you do. If the data is already sorted, that works too, but it isn't always.

I don't see the issue with the binary search yet. Remember that you must sort a list to binary search it, else it will fail, and IMHO the effort to sort counts against the search, at least for the first one. If you search the list a bunch, the sort effort goes to zero the more searches you do. If the data is already sorted, that works too, but it isn't always.

Last edited on

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