Sine Wave Visualizer (Compatible with any terminal size)

sinloop.c

// sinloop.c
// Compile with '-lm'

#include <stdio.h>
#include <unistd.h>
#include <stdbool.h>
#include <math.h>
#include <sys/ioctl.h>

#define WIDTH wsize.ws_col

struct winsize wsize;
float d = 0;
int r = 0;

int main() {
    ioctl(STDOUT_FILENO, TIOCGWINSZ, &wsize); // Gets the window size
    int fill[WIDTH];
    // Sets all elements of the array 'fill' to 0
    for (int i = 0; i < WIDTH; i++) {
        fill[i] = 0;
    }
  
    while (1) {
        r = sin(d) * 10;
        fill[r + (WIDTH / 2)] = 1;
      
        for (int i = 0; i < WIDTH; i++) {
            if (fill[i]) {
                printf("O");
            } else {
                printf(" ");
            }
         }
      
         // Sets all the elements of array 'fill' to 0 again
         for (int i = 0; i < WIDTH; i++) {
            fill[i] = 0;
         }
      
         printf("\n");
         usleep(100000); // Sleep for one tenth of a second
         d += 0.5;
    }
  
    return 0;
}

Will work only on Linux. (Or any Linux environment like Git Bash and Cygwin).
Change the sin() function to a cos() function to get a cosloop!