C++ :

#include<iostream>
using namespace std;
int main()
{
  for(int i=1;i<=26;++i)
  {
	  for(int j=1;j<=26-i;j++) cout<<" ";
	  for(char m=97;m<=96+i;m++) 
	  {
		  if(m==97)cout<<m;
			else
		 cout<<" "<<m;
	   }
		cout<<endl;
   }
	return 0;
}