Question

Correct this Binary Search (C++)

// This program demostrates linear search algorithm

#include <iostream>

using namespace std;
// Binary search algorith
// f is the first , l is the last , t is the target
int binarySearch(int stgrade[], int f, int l, int t)
{
while (f <= l)
{
int m = f + (l - l) / 2;

// Check if x is present at mid
if (stgrade[m] == t)
return m;

// If x greater, ignore left half
if (stgrade[m] < t)
f = m + 1;

// If x is smaller, ignore right half
else
l = m - 1;
}

// if we reach here, then element was not present
return -1;
}
int main(void)
{
int target;
int stgrade[] = { 100, 73, 94, 100, 70, 86, 55, 90, 74 };
// size of the array
int s = sizeof(stgrade) / sizeof(stgrade[0]);

cout << "This is your list" << endl;
for (int i = 0; i < s; i++)
cout << stgrade[i] << " ";
cout << endl;

cout << "Input the target to find , in or out side of your list" << endl;
cin >> target;

// 0 is the index of 1st element
// s is the size and s-1 is in dext of last element
// target is what you want to find

int result = binarySearch(stgrade, 0, s - 1 , target);

if (result == -1)
cout << "Your target NOT FOUND in the list" << endl;
else
cout << "Your target is in the list " << result + 1 << endl;

system("pause");

return 0;
}

Answer 1

#include <iostream>

using namespace std;

int binarySearch(int stgrade[], int f, int l, int t)
{
while (f <= l)
{
int m = f + (l - l) / 2;

// Check if x is present at mid
if (stgrade[m] == t)
return m;

// If x greater, ignore left half
if (stgrade[m] < t)
return binarySearch(stgrade, m + 1, l, t);

// If x is smaller, ignore right half
else
return binarySearch(stgrade, f, m - 1, t);

}

// if we reach here, then element was not present
return -1;
}

int main(void)
{
int target;
int stgrade[] = { 100, 73, 94, 100, 70, 86, 55, 90, 74 };
// size of the array
int s = sizeof(stgrade) / sizeof(stgrade[0]);

cout << "This is your list" << endl;
for (int i = 0; i < s; i++)
cout << stgrade[i] << " ";
cout << endl;

cout << "Input the target to find , in or out side of your list" << endl;
cin >> target;

// 0 is the index of 1st element
// s is the size and s-1 is in dext of last element
// target is what you want to find

int result = binarySearch(stgrade, 0, s - 1 , target);

if (result == -1)
cout << "Your target NOT FOUND in the list" << endl;
else
cout << "Your target is in the list " << result + 1 << endl;

system("pause");

return 0;
}