Diamond Pattern Program In Java that Most Asked in Interview

Below Java concepts are used to print that patterns

• For Loop
• While Loop
• if..else

1). Program to print Half Pyramid Pattern using Star(*) in Java

import java.util.*;  
class Main{
    public static void main(String ...a){
    int i,j,k;
    Scanner sc= new Scanner(System.in);
    System.out.print("enter the number of row for half diamond: ");  
    int n= sc.nextInt();  
    for(i=1;i<=n;i++)
    {
	   for(k=1;k<=i;k++){
                     System.out.print("*");
		    }
		 System.out.println("");
	    }
	for(i=n;i>1;i--)
    {
	    for(k=i;k>1;k--){
                     System.out.print("*");
		    }
		 System.out.println("");
	    }
    }
} 

Output

enter the number of row for half diamond: 5
*
**
***
****
*****
****
***
**
*

2). Program to print left half diamond pattern using star(*) in Java

import java.util.*;  
class Main{
    public static void main(String ...a){
    int i,j,k;
    Scanner sc= new Scanner(System.in);
    System.out.print("Enter the number of row for half diamond: ");  
    int n= sc.nextInt();  
    for(i=0;i<n;i++)
    {
	    for(j=0;j<n-i;j++){
                     System.out.print(" ");
		    }
		    for(k=0;k<=i;k++){
		        System.out.print("*");
		}
		 System.out.println("");
	    }
	 for(i=n-1;i>0;i--)
    {
	    for(j=n;j>=i;j--){
                     System.out.print(" ");
	    }
	    for(k=i;k>0;k--){
		        System.out.print("*");
		}
		 System.out.println("");
	    }
    } 
} 

Output

Enter the number of row for half diamond: 5
     *
    **
   ***
  ****
 *****
  ****
   ***
    **
     *

3). Program to print full diamond pattern using star(*) in Java

import java.util.*;  
class Main{
    public static void main(String ...a){
    int i,j,k;
    Scanner sc= new Scanner(System.in);
    System.out.print("enter the number of row for full diamond: ");  
    int n= sc.nextInt();  
    for(i=0;i<n;i++)
    {
	    for(j=0;j<n-i-1;j++){
                     System.out.print(" ");
	    }
	    for(k=0;k<2*i+1;k++){
		        System.out.print("*");
		}
		 System.out.println("");
	    }
	 for(i=n-1;i>0;i--)
    {
	    for(j=n-1;j>=i;j--){
                     System.out.print(" ");
	    }
	   for(k=2*i-1;k>0;k--){
		        System.out.print("*");
		}
		 System.out.println("");
	    }
    } 
} 

Output

enter the number of row for full diamond: 5
    *
   ***
  *****
 *******
*********
 *******
  *****
   ***
    *