Terminal resizeable box

box.c

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

#define clear() printf("\033[H\033[J")
#define gotoxy(x,y) printf("\033[%d;%dH", (y), (x))

void limitFPS(int fps) {
	usleep((int)round(1000000 / fps));
}

void printbox(int width, int height) {
	printf("+");
	for (int i = 0; i<width - 2; ++i) {
		printf("-");
	}
	printf("+");
	for (int i = 0; i<height - 2; ++i) {
		printf("|");
		for (int j = 0; j<width - 2; ++j) {
			printf(" ");
		}
		printf("|\n");
	}
	printf("+");
	for (int i = 0; i<width - 2; ++i) {
		printf("-");
	}
	printf("+");
}

int main (void) {
	struct winsize win;
	clear();
	while (true) {
		gotoxy(0, 0);
		ioctl(0, TIOCGWINSZ, &win);
		printbox(win.ws_col, win.ws_row);
		limitFPS(60);
	}
	return 0;
}