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C++ program to print pattern of stars till N number of rows

This C++ program will read total number of rows from the user and print the star pattern till N rows.
Submitted by Abhishek Pathak, on May 25, 2017 [Last updated : February 27, 2023]

Printing pattern of stars till N number of rows

While pattern programs are just based on a couple of logic statements, with a repeating pattern on every iteration, they are quite tricky to code. You must have heard about the triangular pyramid pattern, which prints a character in a pyramid fashion.

Generally these patterns are represented with "*" symbol. However, you can always use the character of your choice.

C++ code to print pattern of stars till N number of rows

#include <iostream>
using namespace std;

int main()
{
    int i, space, rows, k = 0;

    cout << "Enter the number of rows: ";
    cin >> rows;

    for (i = 1; i <= rows; i++) {
        for (space = 1; space <= rows - i; space++) {
            cout << "  ";
        }
        while (k != (2 * i - 1)) {
            cout << "* ";
            k++;
        }
        k = 0;
        cout << "\n";
    }

    return 0;
}

Output

Enter the number of rows: 5
        *
      * * *
    * * * * *
  * * * * * * *
* * * * * * * * *

Solution Explanation

Starting with the variables, we have used a space variable that will count the space, rows variable that will hold the number of rows. The i and k variables are loop counters.

After taking rows input from the user, we start a loop to traverse all the rows. Inside it, we use another for loop with space variable in it. This is to ensure that on every row, there are i characters and (row-i) spaces. Next, we check while k is not equal to twice the rows minus 1, we put a star symbol and increment the k.

After the loop we reset k=0 and print a new line.