Help to print reverse array

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C++

#include <iostream>
#include <iomanip>

using namespace std;

const int sentinel = 0;

const int arraysize = 10;

int main()
{
	cout << fixed << showpoint << setprecision(2); // format to 2 decimals

	int array[arraysize]; // declare an array item of 10 components
	int number;

	int count = 0;


	for ( int i = 0; i < arraysize; i++)
		array[i] = 0;
	cout <<"Please enter ints, " << sentinel << " to quit: ";
	cin >> number;


	while (number != sentinel && count < arraysize)
	{
		array[count++] = number;
		cin >> number;
	}

	cout << endl;
	cout << "The original array: ";
	for (int i = 0; i < count; i++)
		cout << array[i] << ' ';
	cout << endl;



	int temp;
	for (int i = 0; i < arraysize/2; i++)
	{

		temp = array[arraysize-1-i];
		array[arraysize - i - 1] = array[i];
		array[i] = temp;
	}

	cout << "The reverse array: ";
	for (int i = 0; i < arraysize; i++)
		cout << array[i]<< ' ';
	cout << endl;

	return 0;

}

What I have tried:

I tried to print reverse if the original value is 1 2 3 4 5 6 then I want reverse array to be 6 5 4 3 2 1 not 0 0 0 0 6 5 4 3 2 1

Posted 10-Feb-16 19:13pm

Member 12320065

Updated 10-Feb-16 19:32pm

Patrice T

v3

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4 solutions

Solution 3

I would try something like that.

C++

int temp;
for (int i = 0; i < count/2; i++)
{

    temp = array[count-1-i];
    array[count - i - 1] = array[i];
    array[i] = temp;
}

cout << "The reverse array: ";
for (int i = 0; i < count; i++)
    cout << array[i]<< ' ';
cout << endl;

Posted 10-Feb-16 19:52pm

Patrice T

Comments

CPallini 11-Feb-16 3:24am

5.

Patrice T 11-Feb-16 7:09am

Thank you

Solution 4

You know, your code could be rewritten this way:

C++

 #include <iostream>
 #include <vector>
using namespace std;

int main()
{
  const int sentinel = 0;
  int n;
  vector <int> v;

  cout <<"Please enter ints, " << sentinel << " to quit: " << endl;

  do
  {
    cin >> n;
    if ( n ) v.push_back(n);
  } while (n);


  cout << "the original array : ";

  for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
    cout << *it << " ";
  cout << endl;

  cout << "the reverse array : ";
  for (vector <int>:: reverse_iterator it = v.rbegin(); it != v.rend(); it++)
    cout << *it << " ";
  cout << endl;

}

Posted 10-Feb-16 21:40pm

CPallini

v2

Solution 2

Hi.

I will do just one change in your code. At line 50, in the loop to print the reverse array, change "for (int i = 0; i < arraysize; i++)" to "for (int i = arraysize - count; i < arraysize; i++)"

C++

cout << "The reverse array: ";
for (int i = 0; i < arraysize; i++)
		cout << array[i]<< ' ';

// change above code to 
cout << "The reverse array: ";
for (int i = arraysize - count; i < arraysize; i++)
		cout << array[i]<< ' ';

Posted 10-Feb-16 19:46pm

rajeev.ra

Updated 10-Feb-16 20:37pm

v2

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OriginalGriff · Accepted Answer · 2016-02-10T19:33:00

Solution 1

Use count - the number of elements the user entered - instead of arraysize in your for loops:

C++

for (int i = 0; i < count/2; i++)
{
    temp = array[count-1-i];
    array[count - i - 1] = array[i];
    array[i] = temp;
}
cout << "The reverse array: ";
for (int i = 0; i < count; i++)
{
    cout << array[i]<< ' ';
}

Posted 10-Feb-16 19:33pm

OriginalGriff

Comments

Patrice T 11-Feb-16 1:56am

Looks like we agree :)
+5

CPallini 11-Feb-16 3:24am

5.