drawing a rhombus

[littlecoco]

I have drawn a rhombus but i think this program is a little bit complicated. Can I have other methods to make it simple? Also, I found that there were some problem when the number of line is an even number. Does a rhombus have an even number line?

Here is my code.

 // This program is about drawing a rhombus.
#include <iostream>
#include <iomanip>
using namespace std;

int main()
{
	int number;
	cout << "Enter a positive integer number: ";
	cin >> number;

	if (number >= 5 && number <= 20)
	{
		int i = 1;
		for (int k = 0; k < (number / 2); k++)
		{
			for (int j = 1; j <= (number / 2) - k; j++)
			{
				cout << " ";
			}
			for (int j = 1; j <= i + k; j++)
			{
				cout << "*";
			}
			i = i + 1;
			cout << endl;
		}
		if (i - 1 == number / 2)
		{
			for (int j = 1; j <= number; j++)
			{
				cout << "*";
			}
			cout << endl;
		}
		for (int k = 1; k <= (number / 2); k++)
		{
			for (int j = 1; j <= k; j++)
			{
				cout << " ";
			}
			for (int j = 1; j <= number - (2 * k); j++)
			{
				cout << "*";
			}
			cout << endl;
		}
	
	}
	else
		cout << "The number is excluded" << endl;
	return 0;
}

[dhayden]

Start with a function that prints a character N times. That way you can get rid of all the inner loops:

void repeatChars(char ch, int times)
{
    for (int i=0; i<times; ++i) {
        cout << ch;
    }
}

Then recognize that the bottom half can be printed exactly the same as the top half, just with the loop iterator going down instead of up:

    if (number >= 5 && number <= 20) {
        for (int k = 0; k < (number / 2); k++) {
            repeatChars(' ', number/2 - k);
            repeatChars('*', 2*k+1);
            cout << endl;
        }

        for (int k = number/2; k >= 0; --k) {
            repeatChars(' ', number/2 - k);
            repeatChars('*', 2*k+1);
            cout << endl;
        }
    }

Now notice that what's inside the loops is identical. So write another function that does that part (maybe call it printLine and use it.