After compile, segmentation fault

#include <unistd.h>

void	ft_putchar(char c)
{
	write(1, &c, 1);
}

void	ft_putnbr(int nr)
{
	unsigned int ui;
	ui = (unsigned int)nr;
	if (ui < 0)
	{
		ft_putchar('-');
		ui = (unsigned int)nr;
		ft_putnbr(ui / 10 + '0');
		ft_putchar(ui % 10 + '0');
	}
	else if(ui >= 10)
	{
		ft_putnbr(ui / 10 + '0');
		ft_putchar(ui % 10 + '0');
	}
	else
	{
		ft_putchar(ui + '0');
	}
}

int	main(void)
{
//	ft_putnbr(42);
	ft_putnbr(-2147483648);
//	ft_putnbr(-10);
//	ft_putnbr(0);
}

c4r6s1% gcc ft_putnbr.c
c4r6s1% ./a.out
--[1] 3509 segmentation fault ./a.out
c4r6s1% vi ft_putnbr.c
c4r6s1% gcc ft_putnbr.c
c4r6s1% ./a.out
--[1] 3548 segmentation fault ./a.out
c4r6s1% gcc -Wall -Werror -Wextra ft_putnbr.c
c4r6s1% ./a.out
--[1] 3593 segmentation fault ./a.out
c4r6s1% vi ft_putnbr.c
c4r6s1% gcc ft_putnbr.c
c4r6s1% ./ft_putnbr.c
zsh: permission denied: ./ft_putnbr.c
c4r6s1% ./a.out
[1] 3824 segmentation fault ./a.out