Write a Java program to print star patterns — right-angled triangle, inverted triangle, and pyramid.

public class StarPattern1 {
    public static void main(String[] args) {
        int n = 5;

        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print("* ");
            }
            System.out.println();
        }
    }
}

*
* *
* * *
* * * *
* * * * *

for (int i = n; i >= 1; i--) {
    for (int j = 1; j <= i; j++) {
        System.out.print("* ");
    }
    System.out.println();
}

* * * * *
* * * *
* * *
* *
*

for (int i = 1; i <= n; i++) {
    // Print spaces
    for (int j = i; j < n; j++) {
        System.out.print("  ");
    }
    // Print stars
    for (int j = 1; j <= (2 * i - 1); j++) {
        System.out.print("* ");
    }
    System.out.println();
}

        *
      * * *
    * * * * *
  * * * * * * *
* * * * * * * * *

// Upper half
for (int i = 1; i <= n; i++) {
    for (int j = i; j < n; j++) System.out.print(" ");
    for (int j = 1; j <= (2*i-1); j++) System.out.print("*");
    System.out.println();
}
// Lower half
for (int i = n-1; i >= 1; i--) {
    for (int j = n; j > i; j--) System.out.print(" ");
    for (int j = 1; j <= (2*i-1); j++) System.out.print("*");
    System.out.println();
}

    *
   ***
  *****
 *******
*********
 *******
  *****
   ***
    *

for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= i; j++) {
        System.out.print(j + " ");
    }
    System.out.println();
}

1
1 2
1 2 3
1 2 3 4
1 2 3 4 5

int rows = 4, cols = 8;
for (int i = 1; i <= rows; i++) {
    for (int j = 1; j <= cols; j++) {
        if (i == 1 || i == rows || j == 1 || j == cols)
            System.out.print("*");
        else
            System.out.print(" ");
    }
    System.out.println();
}

********
*      *
*      *
********