Linear search doesn't work

[TJW]

I tried to compare the comparison times between the linear and binary search. However, the linear search didn't locate the value at all, and kept asking the user to enter another value if I ran it on Visual Studio. It didn't even run on Dev C++, and the error showed [Error] ld returned 1 exit status. Thank you in advance!

#include <iostream>
using namespace std;
//Function prototypes:
int linearSearch(int [], int, int); 
int binarySearch(int [], int, int);
int main()
{
const int SIZE=20;
int array[SIZE]={1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20};
int target=0, linearCount=0, binaryCount=0;
cout << "The numbers in the array in asending order: " << endl;
for(int x=0; x<SIZE; x++)
{
cout << array[x] << " ";
}
cout << endl;
cout << "Please enter the value to locate: ";
cin >> target;
linearCount=linearSearch(array, SIZE, target);
while(linearCount==-1)
{
cout << "The value you are looking for is not in the array." << endl;
cout << "Please enter another value from the list: ";
cin >> target; 
linearCount=linearSearch(array, SIZE, target);//Function call;
}
cout << "The number of comparisons which the linear search made to find the value " << target << " is: " << linearCount+1 << endl;
binaryCount=binarySearch(array, SIZE, target);
cout << "The number of comparisons which the binary search made to find the value " << target << " is: " << binaryCount << endl;
return 0;
}

int linearSearch(int array[], int size, int value)
{
	int index=0;		//Used as a subscript to search array	
	int position=-1;	//Used to record position of search value
	bool found=false;	//Flag to indicate if the value was found
	while(index<size && !found)
	{
		if(array[index]==value)
		{
			found=true;
			position=index;
		}
		index++;
		return position;
	}
}
int binarySearch(int array[], int size, int value)
{
	int first=0,
	    last=size-1,
	    middle,
	    position=-1,
	    count=0;
	bool found=false;
	while(!found && first<=last)
	{
		if(position==-1)
		{
		count++;
		}
		middle=(first+last)/2;
		if(array[middle]==value)
		{
		found=true;
		position=middle;
		}
		else if(array[middle]>value)
		{
		last=middle-1;
		}
		else
		{
		first=middle+1;
		}
	}
	return count;
}

[Ganado]

	while(index<size && !found)
	{
		if(array[index]==value)
		{
			found=true;
			position=index;
		}
		index++;
		return position;
	}

You're returning after the very first iteration, every time.

Move the return out of the while loop.
You are also not using your "found" variable for anything useful.

[TJW]

Thank you, Ganado! Now my program works.
The algorithm was copied from the textbook. I guessed the bool variable found is used as the flag and to control the while loop. I'm new to C++. Let me know if I could write my programs better. Thank you!

[Ganado]

Oh, yes you're correct, I missed that part of it while reading that. Once the return statement is moved out of the loop, the "found" bool does indeed help (to break out of the loop earlier).