C program to print Alphabet Triangle

The below program is to print the Alphabet Triangle in C using loop.
C program to print Alphabet Triangle

#include <stdio.h>
#include<stdlib.h>  
 
void main()
{  
int alpha=97;
int i,j,k,m;    
 
for(i=1; i<=5; i++)    
{   
for(j=5; j>=i; j--)    
printf(" ");  
 
for(k=1; k<=i; k++)    
printf("%c",alpha++);
alpha--;   
 
for(m=1; m<i; m++)    
printf("%c",--alpha);    
printf("\n");    
alpha=97;    
}    
}

Output

      a
     aba
    abcba
   abcdcba
  abcdedcba