How do I turn 1d user input array into a 2d array?

Question

0.00/5 (No votes)

See more:

the code requires us to selection sort the input by the user then turn the selection sorted result into a 2d array by using functions. I have tried searching for it but haven't fully grasped the idea of converting a 1d to a 2d array. The 2d array requires us to have 4 rows and 5 columns.

#include<iostream>
#include<iomanip>

using namespace std;


void getInput(int list[],int dim);
void getSelect(int list1[], int dim);
void convert2DimSort(int list1[], int dim);

int main()
{	
	int dim = 20;
	int list[dim] = {};


	getInput(list, dim);	
	getSelect(list, dim);
	
	for(int i=0;i<20;i++)
	{
		cout<<list[i]<<" "; // how do i convert the result here to 2d array?
	}
	

	return 0;
}


void getInput(int list[], int dim)
{		
	cout<<"enter number: "<<endl;

	for(int i = 0; i<dim; i++)
	{
		cout<<"loc["<<i<<"] ";
		cin>>list[i];
	}
}

void getSelect(int list1[], int dim)
{
	for(int i = 0; i < 19; i++)
	{
		int min = i; 
		
		for(int j=i+1;j<20;j++)
		{
			if(list1[j]<list1[min])
			{
				min=j;
				
			}
		}
		if(min!=i)
		{
			int temp = list1[min];
			list1[min] = list1[i];
			list1[i] = temp;
		}
	}

}

void convert2DimSort
{
	
}

<pre lang="C++">

What I have tried:

I have no idea how to turn the result from a 1dimensional array to a 2dimensional array

Posted 2-Dec-21 19:13pm

Bord 2021

Updated 3-Dec-21 8:58am

v2

Add a Solution

3 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2021-12-02T19:30:00

To convert a 1D array to 2D, you need to decide on the sizes: for example a 20 element 1D array could be converted to a [2, 10], [4, 5], [5, 4], or [10, 2] 2D - so without knowing what your user wants, it's all a bit useless.

The mechanics are easy: allocate a new chunk of memory of the right size (probably with malloc, but it depends on your course so far) then use a nested loop to fill to it.

But I'd start by reading your homework assignment really carefully first - it probably tell you a lot more than you have shown us and it's almost certainly all relevant to the task!

phil.o · Answer 2 · 2021-12-02T22:24:00

Solution 2

Mathematically, the formula for going from a 1D-index to a 2D-index is:

// Given following populated arrays containing same data (initialization not shown):
T[] a1;
T[,] a2;
int N = a1.Length;
// The following yields true for any element:
bool test = a2[i / N, i % N] == a1[i];

Posted 2-Dec-21 22:24pm

phil.o

Comments

Stefan_Lang 3-Dec-21 15:11pm

I doubt this pseudo code will help someone who needs to ask for help on 1- and 2-dimensional arrays.

Your clever way of index conversion likewise is not a suitable answer to a beginner. Besides, you made a mistake there.

Stefan_Lang · Answer 3 · 2021-12-03T08:58:00

Technically, the clean way to copy the elements of a 1d array a to a NxM matrix m would be a nested loop over the rows and columns of the matrix:

C++

int arrayIndex = 0;
for (int row = 0; row < N; ++row) {
    for (int column = 0; column < M; ++column) {
        m[row][column] = a[arrayIndex];
        ++arrayIndex;
    }
}

As you can see, you not only need a double loop to iterate over the elements of the 2D matrix, you also need to maintain the index to the 1d array that you are copying from.

There are simpler solutions, but for now I suggest implementing this in your code and make sure it produces the desired results.

How do I turn 1d user input array into a 2d array?

3 solutions

Solution 1

Solution 2

Solution 3

Add your solution here

Preview 0