Justifying user input string into lines of equal length - c++

Question

So, full disclosure, I have just started learning C++ and this IS part of an assignment. I'm not looking for an answer, just a some guidance.
I'm looking to justify some text in the form of a string into lines of equal length. Both the text and line length are user-input.
What I've got so far is the code below. It works just fine to do the task at hand. I've thrown a bunch of text at it and it's always output the correct formatting for it. However, I am feeling as though I'm going at it the wrong way - the code feels clunky, as if I was forcing it to do something it wasn't designed to do (if you know what I mean).
Should I be looking (or is there) a more elegant way to do what I'm trying to do. I've considered setting up a 2D array of size [width][#lines] so that I can output it line by line. Would that be a preferable way to do things? Is there some sort of "Best Practice" when it comes to this stuff?
#include <iostream>
#include <string>
using namespace std;
int main()
{
string randtext;
string output;
int width;
// User input text string.
cout << "Enter a Random String of Text: " << endl;
getline(cin, randtext);
// User input line width.
cout << "Enter justification Width" << endl;
cin >> width;
int length = randtext.length();
int i = 0;
// This bit parses through the string.
while (i <= length)
{
// This bit creates lines of length = width.
for (int j = 0; j < width; ++j)
{
if (i + j > length) { break; }
char letter = randtext[i+j];
output += letter;
}
// This bit outputs the lines and then clears everything.
cout << output << endl;
output.clear();
i += width;
}
cin.get();
cin.get();
return 0;
}

Answer 1

Your current code has a bug: array indices are 0-based, meaning that 0 to length - 1 are valid, but length is not a valid index. If your goal is to split a string into fixed-sized chunks without any other conditions or constraints, you might consider using string::substr(). This would reduce the amount of code, and make things clearer.
But I'm wondering whether fixed-sized chunks is actually your goal? When I hear "justified" text, I think about text that has been word wrapped (i.e., split on word boundaries) and then spaces inserted so that the left and right edges of each line are aligned. Example:
The quick red fox jumped over the two lazy dogs.
Justified using 14-character line width:
The quick red
fox jumped
over the two
lazy dogs.

Answer 2

Firstly as far as I know there are no best practices. However I would suggest keeping it as simple as possible. I've used a similar approach to what you have done however I have instead inserted a new line character every width interval to the randtext string and then printed that. This dramatically reduces the code size and improves readability. I have tested this against your code and the output is exactly the same. The code is shown below.
#include <iostream>
#include <string>
#include <conio.h>
int main()
{
using namespace std;
string randtext;
int width;
// User input text string.
cout << "Enter a Random String of Text: " << endl;
getline(cin, randtext);
// User input line width.
cout << "Enter justification Width" << endl;
cin >> width;
// Insert a newline character every nth character given that n = width
for (size_t i = 0; i < randtext.length(); i+=width+1)
{
randtext.insert(i,"\n");
}
cout << randtext << endl;
cin.get();
cin.get();
return 0;
}

Answer 3

In case someone stumbles onto this in the future looking for an answer to a similar question, I ended up scrapping my previous code and used SUBSTR (as suggested by #cbranch)to chop up the text and fed it into a VECTOR as follows:
#include <iostream>
#include <string>
#include <vector>
using namespace std;
int main()
{
string input = "The quick brown fox, jumps over the. Lazy dog. There is, no cow. LEVEL";
int width = 20;
int length = input.size();
int j = 0;
vector<string> input_vector (0);
// For loop that chops up the input using input.substr() and feeds it into a vector that re-sizes as needed.
for (int i = 0; i < length; i+=width)
{
// Dynamic vector resizing as needed.
input_vector.resize(j + 1);
string input_sub = input.substr(i, width);
input_vector[j] = input_sub;
j++;
}
int size_vector = input_vector.size();
// For loop that outputs the chopped out lines as elements of the vector.
for (int k = 0; k < size_vector; ++k)
{
cout << input_vector[k] << endl;
}
return 0;
}