C++ Program to Print Triangle of Numbers in Reverse Pattern

Write a C++ program to print triangle of numbers in reverse pattern using for loop.

#include<iostream>
using namespace std;

int main()
{
	int rows;

	cout << "Enter Triangle of Numbers in Reverse Rows = ";
	cin >> rows;

	cout << "Triangle of Numbers in Reverse Order Pattern\n";

	for (int i = rows; i >= 1; i--)
	{
		for (int j = 1; j < i; j++)
		{
			cout << " ";
		}
		for (int k = i; k <= rows; k++)
		{
			cout <<  k << " ";
		}
		cout << "\n";
	}
}

C++ program to print the triangle of numbers in reverse pattern using a while loop.

#include<iostream>
using namespace std;

int main()
{
	int i, j, k, rows;
	
	cout << "Enter Rows = ";
	cin >> rows;

	cout << "Triangle of Numbers in Reverse Order Pattern\n";
	i = rows;

	while (i >= 1)
	{
		j = 1;
		while (j < i)
		{
			cout << " ";
			j++;
		}

		k = i;
		while (k <= rows)
		{
			cout << k << " ";
			k++;
		}

		cout << "\n";
		i--;
	}
}

Enter Rows = 9
Triangle of Numbers in Reverse Order Pattern
        9 
       8 9 
      7 8 9 
     6 7 8 9 
    5 6 7 8 9 
   4 5 6 7 8 9 
  3 4 5 6 7 8 9 
 2 3 4 5 6 7 8 9 
1 2 3 4 5 6 7 8 9 

This C++ example displays the triangle pattern of numbers in descending order or reverse order using the do while loop.

#include<iostream>
using namespace std;

int main()
{
	int i, j, k, rows;

	cout << "Enter Rows = ";
	cin >> rows;

	cout << "\n";
	i = rows;

	do
	{
		j = 1;
		do
		{
			cout << " ";

		} while (j++ < i);

		k = i;
		do
		{
			cout << k << " ";

		} while (++k <= rows);

		cout << "\n";

	} while (--i >= 1);
}

Enter Rows = 10

          10 
         9 10 
        8 9 10 
       7 8 9 10 
      6 7 8 9 10 
     5 6 7 8 9 10 
    4 5 6 7 8 9 10 
   3 4 5 6 7 8 9 10 
  2 3 4 5 6 7 8 9 10 
 1 2 3 4 5 6 7 8 9 10