//Searches a list of numbers entered at the keyboard.
#include <iostream>
using std::cin;
using std::cout;

typedef int* IntPtr;

void fillArray(int a[], int size);
//Precondition: size is the size of the array a.
//Postcondition: a[0] through a[size-1] have been
//filled with values read from the keyboard.

int search(int a[], int size, int target);
//Precondition: size is the size of the array a.
//The array elements a[0] through a[size-1] have values.
//If target is in the array, returns the first index of target. 
//If target is not in the array, returns -1.

int main( )
{
    cout << "This program searches a list of numbers.\n";

    int arraySize;
    cout << "How many numbers will be on the list? ";
    cin >> arraySize;
    IntPtr a;
    a = new int[arraySize];

    fillArray(a, arraySize);

    int target;
    cout << "Enter a value to search for: ";
    cin >> target;
    int location = search(a, arraySize, target);
    if (location == -1)
        cout << target << " is not in the array.\n";
    else
        cout << target << " is element " << location << " in the array.\n";

    delete [] a;

    return 0;
}

//Uses the library <iostream>:
void fillArray(int a[], int size)
{
    cout << "Enter " << size << " integers.\n";
    for (int index = 0; index < size; index++)
        cin >> a[index];
}

int search(int a[], int size, int target)
{
    int index = 0;
    while ((a[index] != target) && (index < size))
        index++;
    if (index == size)//if target is not in a.
        index = -1;
    return index;
}