Downward triangle star pattern means we want to print a triangle that is downward facing means base is upwards and by default, orientation is leftwards so the desired triangle to be printed should look like
* * * * * * * * * *
Example
Java
// Java Program to Print Lower Star Triangle Pattern // Main class public class GFG {
// Main driver method
public static void main(String[] args)
{
// Nested 2 for loops for iteration over the matrix
// Outer loop for rows
int rows = 9 ;
for ( int a = rows - 1 ; a >= 0 ; a--) {
// Inner loop for columns
for ( int b = 0 ; b <= a; b++) {
// Prints star and space
System.out.print( "*"
+ " " );
}
// By now we are done with single row so new
// line
System.out.println();
}
}
} |
Output
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Using Recursion
Java
// added by Manish Sharma import java.io.*;
class GFG
{ public static void printRow( int n)
{
if (n == 0 ) // base case
{
return ;
}
System.out.print( "* " );
printRow(n - 1 ); // next * in the same row
}
public static void nextRow( int n)
{
if (n == 0 )
{
return ;
}
printRow(n); // prints the whole row recursively.
System.out.print( "\n" ); // for new line after printing a row...
nextRow(n - 1 ); // changed to new row
}
public static void main (String[] args)
{
GFG.nextRow( 5 ); // no need to create an object of GFG class as nextRow method is static.
}
} |
Output
* * * * * * * * * * * * * * *
Time Complexity: O(n2), where n represents the given number of rows.
Auxiliary Space: O(1), no extra space is required, so it is a constant.