How do i...print the structure

Learn to indent properly your code, it show its structure and it helps reading and understanding.

#include <stdio.h>

int main()
{
    int i, space, rows,col;
    for(rows=4; rows>=1; rows--)
    {
        for(col=rows;col>=1;col--)
        {
            printf(" %d",col);
        }
        
        for(col=2;col<=rows;col++)
        {
            printf(" %d",col);
        }
        
        printf("\n");
    }

    return 0;
}

Professional programmer's editors have this feature and others ones such as parenthesis matching and syntax highlighting.
Notepad++ Home[^]
ultraedit[^]

Do you have a problem with this code ?

Is this is the output you are looking for:

4 3 2 1 2 3 4
  3 2 1 2 3
    2 1 2
      1

You need to output spaces for the overhangs, this means you always have to print from 4, even if only an empty field. The code change is here:

int main()
{
    int rows, col;

    for (rows = 4; rows >= 1; rows--)
    {
        for (col = 4; col >= 1; col--)
        {
            if (col <= rows)
            {
                printf(" %d", col);
            }
            else
            {
                printf("  ");
            }
        }
        for (col = 2; col <= 4; col++)
        {
            if (col <= rows)
            {
                printf(" %d", col);
            }
            else
            {
                printf("  ");
            }
        }

        printf("\n");
    }

    return 0;
}