diff --git a/TP1/ex4 b/TP1/ex4
new file mode 100755
index 0000000..0cfb818
Binary files /dev/null and b/TP1/ex4 differ
diff --git a/TP1/ex4.c b/TP1/ex4.c
new file mode 100644
index 0000000..c34fe43
--- /dev/null
+++ b/TP1/ex4.c
@@ -0,0 +1,101 @@
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <errno.h>
+#include <time.h>
+
+int		my_atoi(char *str)
+{
+	int i;
+	int posi;
+	int num;
+
+	i = 0;
+	posi = 1;
+	num = 0;
+	while (str[i] == 32 || (str[i] >= 9 && str[i] <= 13))
+		i++;
+	while (str[i] == '-' || str[i] == '+')
+	{
+		if (str[i] == '-')
+			posi = posi * -1;
+		i++;
+	}
+	while (str[i] >= 48 && str[i] <= 57)
+	{
+		num = num * 10;
+		num = num + (str[i] - 48);
+		i++;
+	}
+	return (num * posi);
+}
+
+void	my_putnbr(int nb)
+{
+	char c;
+
+	if (nb < 0)
+	{
+		if (nb == -2147483648)
+		{
+			write(1, "-", 1);
+			write(1, "2", 1);
+			my_putnbr(147483648);
+			return ;
+		}
+		nb = nb * -1;
+		write(1, "-", 1);
+	}
+	if (nb >= 0 && nb < 10)
+	{
+		c = nb + '0';
+		write(1, &c, 1);
+	}
+	if (nb >= 10)
+	{
+		my_putnbr(nb / 10);
+		my_putnbr(nb % 10);
+	}
+}
+
+int	main(int argc, char **argv)
+{
+	pid_t	pid;
+	int	i;
+	int	j;
+	int	n;
+
+	i = 0;
+	j = 0;
+	if (argc != 2)
+	{
+		write(1, "T'es bourré, on veut qu'un seul chiffre qu'on t'dis\n", 53);
+		exit(1);
+	}
+	n = my_atoi(argv[1]);
+	while(j < n)
+	{
+		switch(pid=fork())
+		{
+			case -1 :
+				write(2, "fork foireux\n", 13);
+				exit(errno);
+			case  0 :
+				my_putnbr(getpid());
+				while (i < 10)
+				{
+					my_putnbr(i);
+					write(1, "\n", 1);
+					nanosleep((const struct timespec[]){{0, 500000000L}}, NULL);
+					i++;
+				}
+				exit(2);
+		}
+	j++;
+	}
+        wait(NULL);
+        write(1, "Fin du processus père de pid ", 30);
+        my_putnbr(getpid());
+        write(1, ".\n", 3);
+	exit(0);
+}