How to print compacted points in pure C, so they can be seen as a single mathematical figure (line, square, rectangle, etc.)?

Question

In the following code I'm printing 10 points in a straight line. How can I make these points be compacted so that someone can see all of them as an almost continuous line without, using any graphical library?

#include <stdio.h>
int main()
{
    for (int i=0; i<10; i++)
        printf("%c", '.');
    return 0;
}

Answer 1

          ,
         _o_
    ._ ,'   `o'
----(_)      :       ^aNT
    '  `.   .o
         ~o~  `
          '

A "picture" is worth a thousand words.

Answer 2

How can I make these points be compacted so that someone can see all of them as an almost continuous line without, using any graphical library?

You can´t do that by using points. You need to print fe subsequent _ characters to print a line, fe:

printf("_______________");

If you want to use vertical lines, use the | character in subsequent calls to printf:

printf("|\n");
printf("|\n");
printf("|\n");
printf("|\n");

or just

printf("|\n|\n|\n|\n|\n");

One example:

#include <stdio.h>

int main(void)
{    
   printf("___________________________\n");
   printf("|    ````        ````     |\n");
   printf("|      X         X        |\n");
   printf("|           O             |\n");
   printf("|                         |\n");
   printf("|   |________________|    |\n");
   printf("|         |____|          |\n");
   printf("|_________________________|\n");
}

Output:

___________________________       
|    ````       ````      |              
|      X         X        |            
|           O             |      
|                         |                               
|   |________________|    |           
|         |____|          |  
|_________________________|

It is not the most beautiful look but that should achieve what you want as far as I understood your question. You don´t need special libraries to accomplish simple graphical illustrations in the console.

How to print compacted points in pure C, so they can be seen as a single mathematical figure (line, square, rectangle, etc.)?

A console is not meant to output shapes and figures like that. Maybe there are some terminals with special fonts, but it is hard if not impossible to achieve.