I'm trying to create a square for 2d array using the size of a string, but it's coming out rectangular

Question

This program is supposed work by having the user input text, end the program using ctrl-z, and then the program puts the string into a square 2D array and then displays it from left to right top to bottom, and then top to bottom left to right. Unfortunately it becomes rectangular rather than a square.

Here's the code I have:

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

int main (int argc, char *argv[], char **env)
{
    string s ; s.clear() ;
    int c = cin.get() ;
    while (!cin.eof())
    {
        s += c ;
        c = cin.get() ;
    }

    for ( int i = 0 ; i < s.length() ; ++i)
    {
        if (!isalpha(s[i]))
        {
            s.erase(i,1) ; // removes non-alphanumeric characters
            --i ;
        }
    }

    int side = 1 ;
    while (side * side < s.length() )
    {
        ++side ;
    }

    cout << endl << side << endl;

    char block[side][side] ;
    int i = 0;
    for (int r=0; r<side; r++)    //This loops on the rows.
    {
        for(int c=0; c<side; c++) //This loops on the columns
        {
            block[r][c] = s[i];
            i++;
        }
    }

    cout << endl;

    for (int r=0; r<side; r++)    //This loops on the rows.
    {
        for(int c=0; c<side; c++) //This loops on the columns
        {
            cout << block[r][c];
        }
        cout << endl ;
    }

    cout << endl ;

    for (int c=0; c<side; c++)    //This loops on the columns.
    {
        for(int r=0; r<side; r++) //This loops on the rows.
        {
            cout << block[r][c];
        }
        cout << endl;

    }
    cout << endl;
    cout << s << endl ;
}

Sample input and output: This is a sample text for encryption

becomes: Thisisasampletextforencryption

Thisis
asampl
etextf
orencr
yption

Taeoy
hstrp
iaeet
smxni
iptco
slfrn

They're supposed to be 6x6. Instead they're 6x5 and 5x6.

Answer 1

In your example you are providing 30 characters of input but somehow expecting 36 characters of output (6x6). If you provide an additional character, you will end up with a partial last row/column in each of the displays. If you provide 36 characters of input, you will end up with a complete square for output.

You are reading past the end of the input, which is undefined behavior. You happen to be getting non-printable characters. You should do something like this:

for (int r=0; r<side; r++)    //This loops on the rows.
{
    for(int c=0; c<side; c++) //This loops on the columns
    {
        if (i < s.length())
        {
            block[r][c] = s[i];
        }
        else
        {
            block[r][c] = '*';  //or put anything else you want here
        }
        i++;
    }
}