Triangular matrix (using array)

#include<stdio.h>
#include<conio.h>
#define size 4
void main()
{
int mat[size][size]={0},i,j;
printf("Enter 6 elements of matrix :\n");
for(i=0;i<3;i++)
for(j=0;j<=i;j++)
scanf("%d",&mat[i+1][j]);

printf("Triangluar matrix so formed is :\n");
for(i=0;i<size;i++)
{
for(j=0;j<size;j++)
printf("%3d",mat[i][j]);
printf("\n");
}
getch();
}

Output :