Thread: Arrays, how to find if some number is the element of an array.

Well im trying to figure out arrays and such and working on a program to find if a number inputed by the user belongs to a particular array. this is what i have so far and im kinda stuck as i got no idea how to make the next step.

So i have initialized 2 arrays with different numbers and im asking the user to find a number. When the user lets say, enters 4. The program should say 4 is in ArrayA, if the user enters 7 then the program should say 7 is in ArrayB. Any suggestions?

Code:

#include <iostream>
using namespace std;

int main()
{
	

	int ArrElement;
	int *pArrElement =&ArrElement;

	int ArrayA[8];
	int ArrayB[8];

	for (int i =0; i<5; i++)
	{
		ArrayA[i] = i+1;
		cout << "ArrayA["<< i << "]: " << ArrayA[i] << "\n";
		cout <<"\n";
	}

		for (int j=5; j<10; j++)
		{
			ArrayB[j] = j+1;
			cout << "ArrayB["<< j << "]: " << ArrayB[j] << "\n";
			cout <<"\n";
		}

		cout << "Find a number between 1 and 10 \n";
		cin >> ArrElement;
		cout << *pArrElement << " belongs to ArrayA\n";


	return 0;
}

in not very familiar with lists or vectors yet so thats why. I search for Binary search and it looks promising, as it is better than brute force, but now i gotta figure out how it works and not just what it does.

Oh another question. The book im studying from Sams Teach yourself C++, says that you can combine 2 arrays and make a 3rd array. But it doesnt explain how that is done. my other step on this would be to find 1 element from each array, delete those values from the arrays that they belong and save them into the 3rd array. Any suggestion, or if there is any other better way to do this?

you do realise your code will crash?

Originally Posted by InvariantLoop

Code:

	int ArrayB[8];

		for (int j=5; j<10; j++)
		{
			ArrayB[j] = j+1; // oh dear, accessing ArrayB[9] on an 8 element array

besides that you want std::find

Originally Posted by ChaosEngine

you do realise your code will crash?


besides that you want std::find

it doesnt crash, ive already tested it, i get 0 errors, 0 warnings.

it doesnt crash, ive already tested it, i get 0 errors, 0 warnings.

The point isn't whether your program crashes or not. When you access an index that is out of bounds, the behavior is undefined and therefore doing so will cause unpredicatable results. An array of size 7 has index values that run from 0-6.

my other step on this would be to find 1 element from each array, delete those values from the arrays that they belong and save them into the 3rd array. Any suggestion, or if there is any other better way to do this?

Omit the delete part, and you've got it

i understand what you mean.