Template<class T> to partially fill array

[edman]

I need to create a function that uses a template to partially fill any array and from there search for a value in the array and return its position if found. The program below finds the values for double and int but I do know how to partially fill the array with string or char values. Could someone please help.

//This is the file SearchArrayValue.cpp
//Searches a partially filled array for a number and returns the position of the number if found and
//-1 if not
#include <iostream>
const int SIZE_DECLARED = 10;

template<class T>
void fill_array(T values[], int size, int& number_used);
//Pre condition: 
//Post condition: number_used is the number of elements used in the array
//The array is filled with non negative number from values[0] to values[number_used - 1]
//Values will be entered from the keyboard

template<class T>
T search_array(const T values[], int number_used, T search_value);
//Pre condition: array values is filled with <= number_used values
//Post condition: search_value will be searched in the array and if found the position will be returned
//otherwise -1 will be returned

template<class T>
void display_result(T search_value, int search_result);
//Pre condition:
//Post Condition: The position of the searched item in the array is displayed if it was found
//otherwise the appropriate message is returned.

using namespace std;
int main()
{
	int number_used;
	int int_values[SIZE_DECLARED];
	double double_values[SIZE_DECLARED];
	char char_values[SIZE_DECLARED];
	fill_array(int_values, SIZE_DECLARED, number_used);
	fill_array(double_values, SIZE_DECLARED, number_used);
	fill_array(char_values, SIZE_DECLARED, number_used);
	
	
	cin.get();//To keep console window open
	cin.get();//To keep console window open
	return 0;
}

template<class T>
void fill_array(T values[], int size, int& number_used)
{
	T next, search_value;
	int index = 0, search_result;
	char limit = '.';
	cout << "Enter a maximum of " << size << " non negative values: \n";
	cout << "(Enter a 0 to stop entry) \n";
	cin >> next;
	while ((next >= 0)&&(index < size))//||((next != limit)&&(index < size))
	{
		values[index] = next;
		index++;
		cin >> next;
	}
	number_used = index;

	cout << "Enter number/char to search for: ";
	cin >> search_value;
	search_result = search_array(values, number_used, search_value);
	display_result(search_value, search_result);
}
template<class T>
T search_array(const T values[], int number_used, T search_value)
{
	int index = 0;
	bool found = false;
	while ((!found) && (index < number_used))
		if (search_value == values[index])
			found = true;
		else
			index++;

	if (found)
		return index;
	else
		return -1;
}

template<class T>
void display_result(T search_value, int search_result)
{
	if (search_result == -1)
		cout << "The number " << search_value << " is not in the list" << endl << endl;
	else
		cout << "The number " << search_value << " was first found at values["
		<< search_result << "] of the array" << endl << endl;
}

[Duoas]

Ah, I see the problem.

On line 52 you are assuming something about the input with (next >= 0) . (According to the instructions it should be (next > 0) .)

If you wish to use a semaphore item to terminate input, it must be passed as argument to the function.

However, a better idiom is to forget the semaphore stuff. Users consider it unnatural. Rather, accept a blank line as end of input. For this you'll need to #include <string> and <sstream>.

#include <iostream>
#include <limits>
#include <sstream>
#include <string>
using namespace std;

...

template<class T>
void fill_array(T values[], int size, int& number_used, const string& itemname );

...

int main()
  {
  ...

	fill_array(int_values, SIZE_DECLARED, number_used, "integer");
	fill_array(double_values, SIZE_DECLARED, number_used, "floating-point number");
	fill_array(char_values, SIZE_DECLARED, number_used, "character");

  ...
  }

template<class T>
void fill_array(T values[], int size, int& number_used, const string& itemname )
{
	T next, search_value;
	int index = 0, search_result;
	cout << "Enter a maximum of " << size << ' ' << itemname << "s: \n";
	cout << "Press ENTER on a blank line to end.\n";

	string s;
	while (getline( cin, s ) && !s.empty() && (index < size))
	{
		stringstream ss( s );
		while ((ss >> next) && (index < size))
		{
			values[index] = next;
			index++;
		}
	}
	number_used = index;

	cout << "Enter a " << itemname << " to search for: ";
	cin >> search_value;
	cin.ignore( numeric_limits <streamsize> ::max(), '\n' );
	search_result = search_array(values, number_used, search_value);
	display_result(search_value, search_result);
}

There are a few other things I dislike (like accessing cin and cout directly in a template function, or having the entry function call the search and display functions...), but those aren't critical (atm).

Hope this helps.

[edman]

Thank you Duoas. I will try it.