Hi

I am testing myself by making a simple program that reverses the contents of an array. It works for some values but the last value of the array is not correct.

Can you take a look over my code to point out where its going wrong?

the original array is:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

the output of my program is:

1, 4247750
2, 19
3, 18
4, 17
5, 16
6, 15
7, 14
8, 13
9, 12
10, 11
11, 10
12, 9
13, 8
14, 7
15, 6
16, 5
17, 4
18, 3
19, 2
4247750, 1


4247648, 4247750, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,

And finally my code:

#include <iostream>
#include <fstream>

using namespace std;

void reverse_array(int array[]);

void alt_reverse_array(int array[]);

int main()
{
	int array1[20];

	ifstream infile;

	infile.open("numbers.txt");

	if (!infile)
	{
		cout << "Failed to open file";
		return 0;
	}

	for (int i = 0; i < 19; i++)
	{
		infile >> array1[i];
	}

	reverse_array(array1);
	alt_reverse_array(array1);


	return 0;
}

void reverse_array(int array[])
{
	int reverse_array[20];
	int count = 0;


	for (int i = 19; i >= 0; i--)
	{
		reverse_array[count] = array[i];
		count++;
	}

	for ( int i = 0; i <= 19; i++)
	{
		cout << array[i] << ",  " << reverse_array[i] << endl;
	}
	cout << "\n\n";
}

void alt_reverse_array(int array[])
{
	int a = 0;
	int b= 20;
	int temp = 0;

	for (int i = 0; i < 19; i++)
	{
		temp = array[a];
		array[a] = array[b];
		array[b] = temp;
		a++;
		b--;
	}

	for (int j = 0; j < 19; j++)
	{
		cout << array[j] << ",  ";
	}
}
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