Row transposition cypher using extra column - c++

Question

Hi guys I am trying to make a program that takes some user input and maps it to a 2d array and then encrypts it by mixing up the columns. For example if the user enters "my name is fred" the program creates an array that is 3x6 filling the last column with y's and the remain empty spaces with x's so it should be something like
mynamy
eisfry
edxxxx
instead I wind up with
mynam
eisfr
edxx
#include <iostream>
#include<cctype>
#include<algorithm>
using namespace std;
main(){
string input;
cout << "Enter information to be encrypted" << endl;
getline(cin,input);
input.erase(std::remove (input.begin(), input.end(), ' '), input.end());
int columns = 6;
int rows;
if (input.size() <= 5){
rows = 1;
}
else if (input.size()% 5 > 0){
rows = input.size()/5 + 1;
}
else
rows = input.size()/5;
char message[rows][columns];
int place = 0;
for(int i = 0; i < rows; i++){
for(int j = 0; j < (columns-1); j++){
if(place <= input.size()){
message[rows][columns] = input[place];
}
else {
message[rows][columns] = 'x';
}
place++;
message[rows][5] = 'y';
cout << message[rows][columns];
}
cout << endl;
}
}

Answer 1

this should do it..
#include <iostream>
#include <cctype>
#include <algorithm>
using namespace std;
int main()
{
string input;
cout << "Enter information to be encrypted" << endl;
getline(cin,input);
input.erase(std::remove (input.begin(), input.end(), ' '), input.end());
int columns = 6;
int rows;
if (input.size() <= 5){
rows = 1;
}
else if (input.size()% 5 > 0){
rows = input.size()/5 + 1;
}
else
rows = input.size()/5;
char message[rows][columns];
for(int i = 0; i < rows; i++){
for(int j = 0; j < (columns-1); j++){
if ((i*5 + j) < int(input.size())){
message[i][j] = input[i*5 + j];
}
else {
message[i][j] = 'x';
}
// place++;
if (i != rows-1) message[i][5] = 'y';
else message[i][5] = 'x';
// cout << "i: " << i << " | j: " << j << " | " << message[i][j] << endl;
}
cout << endl;
}
for (int i = 0; i < rows; i++) {
for (int j = 0; j < columns; j++) {
cout << message[i][j];
}
cout << " ";
}
cout << endl;
}

Answer 2

Your code isn't actually doing anything to transpose the matrix! It's writing the message into the matrix, but it's printing each entry out right after it's written, so it doesn't end up changing the order at all.
You'll need a separate set of loops to read data out of the matrix.