I just started with C, but I had some knowledge of PHP, so I decided to do some 'more complicated' stuff, as for a beginner :)
I used two nested loops to print an 50x50 array. It isn't very slow, but I included a movement with arrow keys to it to move one symbol, X (player) around the array. Every time a move is made, whole array needs to be refreshed, which I did by:
system("cls");
for(x=0;x<50;x++)
{
for(y=0;y<50;y++)
{
printf("%c",table[x][y]);
}
printf("\n");
}
Which is very sloppy solution and whole array 'blinks' while it refreshes after every move.
Is there any more efficient way of doing that in C?
You would probably have to use some sort of shell graphics library like ncurses to move stuff around your array without it blinking when you redraw it. There's not really a simple way to avoid that when you're just using printf to display your grid as output.
I assume you're using Windows (because of the cls).
Maybe ANSI.SYS escape sequences are the simplest way without a library.
You can probably avoid flickering if you move the cursor and overwrite the display contents without clearing the old contents.
There's an example on "Reading and Writing Blocks of Characters and Attributes" with the Win32 Console:
http://msdn.microsoft.com/en-us/library/ms685032%28v=vs.85%29.aspx
Edit: explained the link.
Related
So I am currently learning how to program in c and till now I've been making great process. I decided to make myself a matrix in which a character ('0') can be freely moved around using wasd.
Now there is the issue of keys repeating themselves making it impossible to move into two directions. Perhaps you know how if you hold a key on your keyboard it repeats itself quickly. This causes if I press for example w and a to fist go one up and then just to the left and not vertically. Is there any sort of argument that I can put in my code to prevent this (I'm using getchar())
So I am working on this side project game kinda thing, and I want to put it inside of a border/box. I then want to print text constantly inside that border: adding text, removing it, changing it etc. I've looked far and wide, and cannot find anyway to print inside the box separately from the actual box.
My current implementation is to clear screen, and then reprint the entire box with new text using this:
printf("\e[1;1H\e[2J");
The issue with this is that I get this very obnoxious blinking effect, because every iteration of clearing my screen causes that portion of the screen to become black for a certain period of time.
So I am looking for a few solutions.
How to print a border separate from the print statement inside of it. I currently am implementing it like such:
printf("| | Hello There ||\n");
, and then repeating that all the way down to make a border.
How to completely overwrite the already outputted text so that this blinking effect can go away. So imagine \r removing a line, I want something like that, that removes the whole text and replaces it with a new set of text
How to change the location of where the user inputs into the console, so you can type into a box
Those are basically the only solutions I could think of, if you have any others I'd love to hear them
I also had a general question about c.
conio.h, graphics.h, windows.h and a few other headers don't work for my compilers. I use ubuntu, and they always come up with some error saying I can't use them. I appreciate someone explaining this to me.
Please let me know what you think, and if you need more info, I'll be sure to provide it
-Ryan
conio.h and windows.h are not standard Linux libraries, so they won't compile on Linux unless you install extra software. One solution would be to use a library designed for managing the screen like ncurses.
You can do that with loops and ASCII characters similar like that:
#include <stdio.h>
int main()
{
int i;
printf("\n\t\t═");
for(i=0;i<=20;i++)
{
printf("═");
}
for(i=0;i<=22;i++)
{
printf("\t\t║\n");
if(i==10)
{
printf("\t\t\tHello There \t\n");
}
printf("\t\t\t\t\t║\n");
}
printf("\t\t═");
for(i=0;i<=22;i++)
{
printf("═");
}
return 0;
}
How do you make a breakable loop in Scratch? I'm using Scratch 2.0 and can't find any good way to make a loop breakable, from inside of the loop itself.
Disclaimer:
There is no perfect way to do it. If you can possibly stand this true fact then feel free to continue.
There are a few different ways you could do it.
With repeat until
The first and most simple one follows this:
But this isn't technically part of the script - it's just repeating until some value returns true.
With a custom block (stop this script)
In order to do it inside of the script, you'll need to use a sneaky little trick with custom blocks.
Create a custom block called whatever you want - but probably along the lines of "breakable loop". Inside of it, create this script:
By using stop script we are breaking out of the script that is currently running - which, according to Scratch, is the custom block.
See the result! (as scratchblocks)
With broadcast and wait
You could also use a broadcast-and-wait method, very similar to above:
Though I highly suggest you don't use this method, as if any other sprites have breakable loops you'll need to rename each one, which can be tedious after using a lot of loops in a lot of sprites!
(Note this bug has been fixed in version 442 of the editor and such the following no longer applies.)
Help! My project is lagging a bunch now!
As #foi has noticed, if your code must be run inside of a frame you probably checked run without screen refresh. Unfortunately, due to a bug in the Scratch player, this causes the program to essentially break after the stop this script block has been activated. How can you handle this?
It follows the same principle you use when you use a run without screen refresh custom block inside of a forever loop - the loop doesn't use screen refresh while the inside does, allowing for instant animations whether or not one is using turbo mode.
Here's an example - the image is really too long to be embedded, so see it here instead.
You can make a variable inside or outside of the repeat and make your script like this:
repeat until [[my variable] = [e.g: 1]]
your code
your code
your code
your code
end of repeat until
For a "repeat until" block the simplest way would be to "or" your normal until condition with the break condition in the until.
By adding an incremeting loop counter variable in the loop you can use a "repeat until" to replicate the function of a "repeat n times" block
By using a "repeat until" block with only your break condition you get the equivalent of a "forever" block
If you need another script/ sprite to trigger the break then a public variable will let you break the loop from anywhere and let a single condition break loops for different sprites.
I'd post an image of the blocks but this is my first reply and the site won't let me!
good luck
You can use these few ways to do it...
conditional loop
stop this script
if then else, in the else section, put nothing
I would prefer to use the first method, as it requires less blocks and for the first method, you can still add in code that will be executed after the loop has stopped executing.
You can make it repeat x times or make it have a certain point where it stops, such as another variable changing.
Otherwise, I don't think there is a wat to do that.
Use the repeat until block. Then put in an equals block or whatever into the boolean part. Then inside that repeat until block, put a stop this script block.
Hope this helps :D
I'm trying to find an algorithm for the game master mind with 4 numbers, where each number can be between 0 to 5, giving 1296 possibilities. With the first guess being 1,1,0,0
there are less options left.
I would like to know how to remove the options which are not suitable according to the first guess.
How to use an array(solutions) and array(current solutions)? Should I use parameterization for that?
Is there an algorithm in C to do that?
Thanks a lot for the help!
The simplest to implement is to simply loop trough all your elements and make the once that no longer work false. This might be the best idea here as looping trough 1300 elements is still quite fast however be aware that there is a faster solution in just finding which type of solutions are no longer available.
For mastermind there are multiple algorithms, see wikipedia, however for your first implementation I think they are too difficult.
You could start by using either
Thijser's idea (slightly better than brute-forcing all possibilities),
or try to emulate a human player: using that a white key-peg means correct color in wrong position and a black key-peg meaning correct color in correct position. You can write an easy recursion to take that info into account:
white-peg -> move the colors around ;
black-peg remove colors to find out which of the colors was the one that was correct-in-correct-pos.
I have a application that will capture the screen and I want to write the captured information to an array, this takes AGES as the array ends up being +2million values. I am iterating and adding the values to the array, is there any way quicker (eg binary operations)? Should it be this slow? Why is it?
Assuming your GetPixel'ing the screen pixel by pixel, its the GetPixel call that's slow (it interrogates the display driver) not the (pre-dimensioned) array assignment.
You can instead use the getdibits() api which will copy the DC's colour info into a buffer in a single call.
Here is a C++ example, but the methodology & call sequence is the same as for VB.
Figured out why it was so slow, it was because I was using ReDim on every iteration of the loop - thanks for the help anyways
Martin