2020-03-24
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NPTEL,SWAYAM,JAVA,Programming
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NPTEL WEEK 8 Q 4 : JAVA Programming Solution 2020

Write a program to print symmetric Pascal's triangle of "*" 's of height "l" of odd length . If input "l" is even then your program will print "Invalid line number".

For example:

input : 5

output:

* *

* * *

* *

input : 6

output:

Invalid line number

Note: Spaces must be exactly same as in the example for correct evaluation.

Select the Language for this assignment.

File name for this program :

import java.util.*;
public class Pattern4 {
    public static void main(String[] args) {
        Scanner inr = new Scanner(System.in);
      int l = inr.nextInt();
        // Add the necessary code in the below space
​
      int ul=0; // Upper Line
    int ll=0; // Lower Line
        
    // Check whether line number is odd
    if (l%2!=0){
       ul=(l/2)+1;          
       ll=l-ul;
    //Code for upper half
    for(int i=1;i<=ul; i++){    
    //Space management
    for(int s=1;s<=(ul-i); s++){
        System.out.print(" ");
    }
    // Star management
    for(int j=1;j<=i; j++){
         System.out.print("* ");
    }
    System.out.println();
    }
            
    //Code for lower half
    int llc=ll;
    for(int i=1;i<=ll; i++){
    //Space management
    for(int s=llc;s<ll; s++){
       System.out.print(" ");
    }
    // Star management
    for(int j=1;j-1<=ll-i; j++){
       System.out.print(" *");
     }
     llc--;
    System.out.println();
        }
    }
        else{
       System.out.print("Invalid line number");
    }
​
    }
}