Reversing Rectangle character after certain height - c++

Question

I am stuck in some tricky part. I have to reverse the rectangle character after certain height in c++ like below
111111111
122222221
123333321
123333321
122222221
111111111
in above i have to reverse rectangle character after height 3. My code works well in for first three rows but it didn't work for reversing. Input Rows 6 and Columns 9. Can any one tell where i am doing in my code. Below is my code
void Rectangle(int rows, int cols){
int mid = rows / 2, midcol = cols / 2;
for (int i = 1; i <= rows; i++) {
for (int j = 1; j <= cols; j++) {
if (i > j)
{
if (i <= mid)
{
cout << j;
}
else if (j < midcol)
{
cout<< j;
}
else if (j == midcol)
{
cout<<cols - j - 1;
}
else
{
cout<<cols - j;
}
}
else if (i > cols - j)
{
cout<< cols - j + 1;
}
else
{
cout<< i;
}
}
cout << endl;
}
}
int main() { // Get the number
int row;
int columns;
cout<<"plase enter a Row height:";
cin >> row;
cout<<"plase enter a Columns:";
cin >> columns;
Rectangle(row, columns);
system("pause");
return 0;
}

Answer 1

We can observe the following.
Up to the mid column, the values are the column values, but not higher then the row values.
Over the middle column the column numbers are revered. What does this mean? If you have 10 columns and want to reverse it, then you have to subtract the column number from the width 10. So
10-6 = 4
10-7 = 3
10-8 = 2
10-9 = 1
10-10 = 0;
The same is valid for the rows.
So, for normal columns (< middle value). the column number
For column numbers above the middle, the reversed column number (see above)
But not bigger then the limited row value
The limited row value is calculated as per the above scheme
In my demo program I use a std::vector<std::vector<int>> to store the values. Calculated values start with 0. So I add 1 for each value add the end.
Please see:
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <iterator>
#include <cmath>
void showRectangle(const size_t height, const size_t width) {
std::vector lines{ height, std::vector(width, 0U) };
// Calculate the vales in the middle
const size_t midHeight{ static_cast<size_t>(std::ceil(height / 2.0)) };
const size_t midWidth{ static_cast<size_t>(std::ceil(width / 2.0)) };
// Iterate over all rows and columns
for (size_t row{ 0U }; row < height; ++row) {
for (size_t column{ 0U }; column < width; ++column) {
// Calculate the vaule for row and column
lines[row][column] = (std::min((column >= midWidth) ? (width - column-1) : column,
(row >= midHeight) ? (height - row - 1) : row)) +1 ;
}
}
// Show output
for (const std::vector<size_t>& vi : lines) {
std::copy(vi.begin(), vi.end(), std::ostream_iterator<size_t>(std::cout));
std::cout << "\n";
}
}
int main() {
// Explain the user that he has to enter the height in rows
std::cout << "\nEnter the height of the rectangle in rows: ";
// Get the height. And check, if input worked
if (size_t height{}; std::cin >> height) {
// Explain the user that he has to enter the width in columns
std::cout << "Enter the width of the rectangle in columns: ";
if (size_t width{}; std::cin >> width) {
// SHow result
std::cout << "\n\nResulting rectangle:\n\n";
showRectangle(height, width);
}
else {
std::cerr << "\n*** Error: wrong input for width\n";
}
}
else {
std::cerr << "\n*** Error: wrong input for height\n";
}
}