How to display a moving array in the output console? - c

Question

What's the better way than what I have done below:
system("cls") does the job but clearing the screen will later on mess with whatever that I want to display, the other negative side effect is the annoying blinks.
#include <stdio.h>
#include <stdlib.h>
int a[5]={1,0,1,1,0};
int b[5]={0,0,1,1,1};
int main()
{
srand(time(NULL));
while(1){
//display the arrays
for(int i=0; i<=4; i++){
printf("%d ",a[i]);
}
printf("\n");
for(int i=0; i<=4; i++){
printf("%d ",b[i]);
}
//shift every cell by 1
for (int i = 4 ; i >= 0; i--) {
a[i] = a[i - 1];
b[i] = b[i - 1];
}
sleep(1);
system("cls");
//keep generating 0s and 1s for the 1st cell of arrays
a[0] = rand() %2;
b[0] = rand() %2;
}
}

Answer 1

Without platform/terminal specific code that is not possible as there is no platform independent way to place the cursor or clear the screen.
The best you can do that is largely platform independent is return to the start of the current line, or back-space on the current line. That is to say you can only move the cursor backward on the current cursor line:
What you can do is:
Replace printf("\n"); with printf("\t");
Replace system("cls") ; with:
printf("\r");
fflush(stdout) ;
The output will be on one line with a TAB separation, and the line will be overwritten on each iteration.
1 1 1 0 1 1 0 1 0 0
Failing that you can either:
Use a platform independent console library such as ncurses,
On windows use the native Windows Console API.
Where supported use ANSI escape sequences.
The last option is simplest and while for a long time was not supported in Windows, Windows 10 now supports ANSI ESC sequences, so there are few reasons not to use that for this simple screen handling.
For example ESC[0;0H moves the cursor to the top-left. In this case you would simply replace the "cls" with:
printf( "\x1b[0;0H" ) ;
Note that in this case you also need either a newline or fflush(stdout) before the sleep() to ensure the second line is output before the clear screen:
printf("\n"); // Force output flush
sleep(1);
printf( "\x1b[0;0H" ) ; // Home cursor
If you have other content on the screen before this and you don't want to redraw everything, you could move the cursor by:
printf("\n"); // Force output flush
sleep(1);
printf( "\x1b[2A" ) ; // Cursor Up two lines