97 is the ASCII (American Standred Code for Information Interchange) code of small 'a'. If we increment the character variable then it turn to 98. i.e. 'b'. Now create a row and column
public class Pattern { public static void main(String []arg) { char ch=97; int r,c,s,n=5; for(r=0;r<n;r++) { ch=97; for(s=0;s<n-r;s++) { System.out.print(" "); } for(c=0;c<=r;c++) { System.out.print(ch); ch++; } System.out.println(""); } } }