C program to print Number Triangle

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

#include <stdio.h>
#include<stdlib.h>  
 
void main()
{  
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("%d",k);
 
for(m=1; m<i; m++)    
printf("%d",m);    
printf("\n");    
}    
}

Output

        1
       121
      12312
     1234123
    123451234