Write a Java program to print hollow sandglass star pattern using for loop.
package Shapes3; import java.util.Scanner; public class HollowSandglassStar1 { private static Scanner sc; public static void main(String[] args) { sc = new Scanner(System.in); int i, j, k; System.out.print("Enter Hollow Sandglass Star Pattern Rows = "); int rows = sc.nextInt(); System.out.println("Printing Hollow Sandglass Star Pattern"); for (i = 1; i <= rows; i++ ) { for (j = 1; j < i; j++ ) { System.out.print(" "); } for(k = i; k <= rows; k++) { if(i == 1 || k == i || k == rows) { System.out.print("* "); } else { System.out.print(" "); } } System.out.println(); } for (i = rows - 1; i >= 1; i-- ) { for (j = 1; j < i; j++ ) { System.out.print(" "); } for(k = i; k <= rows; k++) { if(i == 1 || k == i || k == rows) { System.out.print("* "); } else { System.out.print(" "); } } System.out.println(); } } }

This Java program displays the hollow sandglass pattern of stars using a while loop.
package Shapes3; import java.util.Scanner; public class HollowSandglassStar2 { private static Scanner sc; public static void main(String[] args) { sc = new Scanner(System.in); int i, j, k; System.out.print("Enter Hollow Sandglass Star Pattern Rows = "); int rows = sc.nextInt(); System.out.println("Printing Hollow Sandglass Star Pattern"); i = 1; while( i <= rows ) { j = 1; while( j < i ) { System.out.print(" "); j++; } k = i; while( k <= rows) { if(i == 1 || k == i || k == rows) { System.out.print("* "); } else { System.out.print(" "); } k++; } System.out.println(); i++; } i = rows - 1; while( i >= 1 ) { j = 1; while( j < i ) { System.out.print(" "); j++; } k = i; while( k <= rows) { if(i == 1 || k == i || k == rows) { System.out.print("* "); } else { System.out.print(" "); } k++; } System.out.println(); i--; } } }
Enter Hollow Sandglass Star Pattern Rows = 7
Printing Hollow Sandglass Star Pattern
* * * * * * *
* *
* *
* *
* *
* *
*
* *
* *
* *
* *
* *
* * * * * * *
This Java Program uses the do while loop to print the hollow sandglass pattern of stars.
package Shapes3; import java.util.Scanner; public class HollowSandglassStar3 { private static Scanner sc; public static void main(String[] args) { sc = new Scanner(System.in); int i, j, k; System.out.print("Enter Hollow Sandglass Star Pattern Rows = "); int rows = sc.nextInt(); System.out.println("Printing Hollow Sandglass Star Pattern"); i = 1; do { j = 1; do { System.out.print(" "); } while( j++ <= i ); k = i; do { if(i == 1 || k == i || k == rows) { System.out.print("* "); } else { System.out.print(" "); } } while( ++k <= rows); System.out.println(); } while(++i <= rows ); i = rows - 1; do { j = 1; do { System.out.print(" "); } while( j++ <= i ); k = i; do { if(i == 1 || k == i || k == rows) { System.out.print("* "); } else { System.out.print(" "); } } while( ++k <= rows); System.out.println(); } while(--i >= 1 ); } }
Enter Hollow Sandglass Star Pattern Rows = 11
Printing Hollow Sandglass Star Pattern
* * * * * * * * * * *
* *
* *
* *
* *
* *
* *
* *
* *
* *
*
* *
* *
* *
* *
* *
* *
* *
* *
* *
* * * * * * * * * * *
In this Java example, HollowSandglassPattern function allows user to enter the character and prints the hollow sandglass pattern of the given character.
package Shapes3; import java.util.Scanner; public class HollowSandglassStar4 { private static Scanner sc; public static void main(String[] args) { sc = new Scanner(System.in); System.out.print("Enter Hollow Sandglass Star Pattern Rows = "); int rows = sc.nextInt(); System.out.print("Enter Character for Hollow Sandglass Pattern = "); char ch = sc.next().charAt(0); System.out.println("Printing Hollow Sandglass Star Pattern"); HollowSandglassPattern(rows, ch); } public static void HollowSandglassPattern(int rows, char ch) { int i, j, k; for (i = 1; i <= rows; i++ ) { for (j = 1; j < i; j++ ) { System.out.print(" "); } for(k = i; k <= rows; k++) { if(i == 1 || k == i || k == rows) { System.out.print(ch + " "); } else { System.out.print(" "); } } System.out.println(); } for (i = rows - 1; i >= 1; i-- ) { for (j = 1; j < i; j++ ) { System.out.print(" "); } for(k = i; k <= rows; k++) { if(i == 1 || k == i || k == rows) { System.out.print(ch + " "); } else { System.out.print(" "); } } System.out.println(); } } }
Enter Hollow Sandglass Star Pattern Rows = 15
Enter Character for Hollow Sandglass Pattern = &
Printing Hollow Sandglass Star Pattern
& & & & & & & & & & & & & & &
& &
& &
& &
& &
& &
& &
& &
& &
& &
& &
& &
& &
& &
&
& &
& &
& &
& &
& &
& &
& &
& &
& &
& &
& &
& &
& &
& & & & & & & & & & & & & & &