如何在新行之前创建不可见空间？

Question

I am a beginner of C language. I was recently writing a program to print a histogram of the number of instances of a character in an input. Printing the histogram horizontally is easy, but vertically is a challenge.

Please have a look at the following code:

 #include <stdio.h>

int main()
{

    /*THIS IS JUST A SAMPLE OF WHAT I WANT TO ASK*/
    int occurrence = 5;
    int i;

    for (i=0;i<occurrence;i++){
        printf("\t*\n");
    }




}

For an example, say any letter occurs 5 times. So I have set the occurrence to 5. And I am printing the bar in the form of asterisks. Now through this code, I am able to print an histogram containing 5 asterisks. But the thing is if I want to print other elements, like the x and y axis, the code creates a \\n character. So if I write the code to print other elements, they start printing from the next line. So I figured out something else.

Now read this code:

#include <stdio.h>

int main()
{

    /*THIS IS JUST A SAMPLE OF WHAT I WANT TO ASK*/
    int instances = 5;
    int i;

    for (i=0;i<instances;i++){
        printf("\t*\t\t\t\t\t\t\t\t\t");
    }




}

Now what I did is depending on the size of the output screen, I created 9 tab characters so that the next asterisk moves on to the next line without printing any \\n character.

Now the main question: IS THERE ANY OTHER WAY TO CREATE INVISIBLE SPACES UNTIL THE NEXT THING TO BE PRINTED MOVES ON TO THE NEXT LINE?

This question might be stupid but if there is a solution, it will be best for me.

NOTE: If there is no such method of creating blank spaces then please suggest a good way to create a vertical histogram. If someone wants an improvisation in the question, I am ready to do it.

Thanks for the help!

Outputs::

If I use the first code and I make other chart elements using printf statements, this is the output::

Now can you see that the bar made of asterisks is not aligned with the x and y axis. This happens due to the \\n character.

Answer 1

Instead of hacking around with spaces yourself, you might want to look into a library that handles all that graphical stuff for you. For example, ncurses is a pretty decent library to do pseudo-graphical output on a console. However, "ncurses" seems to be for Unix only, but there may be other libraries for Windows.

If using a library is not an option, I'd suggest to work with a 2-dimensional character buffer (that you treat like a bitmap) instead of writing things directly to the console. It's a lot less "fiddling around". Just watch out to truncate your buffer line size to the console line size before printing, in order to avoid automatic line breaks where you don't want them.

Answer 2

If you do not want to use curses library, for example if you have found a printing terminal in a museum and want that your program can work on it, you have to reverse the problem.

You must print line by line if you do not use a graphic library. So your program could look like :

• compute the occurence of characters
• compute the maximum occurence
• for each line from max occurence to 0
  • compute a line for every character printing a space (not reached)
  • for each character
    • if the occurence is greater than the line index put a mark at correct place in the line
  • print the line

That's the algo, actual coding is left as exercice for the reader :-)

Answer 3

You might want to think about having a two dimensional array. Start by filling it with spaces. Then replace the spaces with the character you want to print at the correct index. Using two for loops, traverse the array in order to print. Print a new line at the end of the row. Changing the order of the index changes a vertical/horizontal print. Negatives are

1. having to keep the whole thing in memory.
2. Needing multiple passes. One to set the characters and another to print.