Recursive program to print triangular patterns
Last Updated :
13 Mar, 2023
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We have discussed iterative pattern printing in previous post.
Examples:
Input : 7
Output :
*
* *
* * *
* * * *
* * * * *
* * * * * *
* * * * * * *
Algorithm:-
step 1:- first think for the base condition i.e. number less than 0
step 2:-do the recursive calls till number less than 0 i.e:- printPartten(n-1, k+1);
step 3:-print the spaces
step 4:-then print * till number
Below is the implementation of above approach:
- C++
- Java
- Python3
- C#
- PHP
- Javascript
C++
// C++ program to print triangular patterns using Recursive #include <iostream> using namespace std; void printPartten(int n, int k) { if (n < 0) // Base condition return; // Recursive call printPartten(n - 1, k + 1); int i; for (i = 0; i < k; i++) // it makes spaces cout << " "; for (i = 0; i < n; i++) // for print * printf("* "); printf("\n"); // for next line } int main() { int n = 7; // Call to printPartten function printPartten(n, 0); return 0; } |
Java
Python3
C#
PHP
Javascript
Output:
*
* *
* * *
* * * *
* * * * *
* * * * * *
* * * * * * *
Time Complexity: O(n2)
Auxiliary Space: O(n), The extra space is used in recursion call stack.
How to print its reverse pattern?
simply Just put the recursive line end of the function
Example:
Input : 7
Output :
* * * * * * *
* * * * * *
* * * * *
* * * *
* * *
* *
*
- C++
- C
- Java
- Python 3
- C#
- PHP
- Javascript
C++
// C++ program to print reverse triangular // patterns using Recursive #include <bits/stdc++.h> using namespace std; void printPartten(int n, int k) { if (n < 0) // Base condition return; int i; for (i = 0; i < k; i++) // it makes spaces cout <<" "; for (i = 0; i < n; i++) // for print * cout <<"* "; cout <<"\n"; // for next line // Recursive calls printPartten(n - 1, k + 1); } int main() { int n = 7; // Call to printPartten function printPartten(n, 0); return 0; } // this code is contributed by shivanisinghss2110 |
C
Java
Python 3
C#
PHP
Javascript
Output:
* * * * * * *
* * * * * *
* * * * *
* * * *
* * *
* *
*
Time Complexity: O(n2)
Auxiliary Space: O(1), As the function becomes tail recursive no extra stack space is required.
