C Programing : Parent & Child Process

C Programing : Parent & Child Process

I'm trying to figure this out, given the following code:
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
char mynum='0';
int main(void)
{
int i;
pid_t fork_return;
static char buffer[10];
fork_return = fork();
if (fork_return == 0)
{
strcpy(buffer, "CHILD"); /*in the child process*/
for (i=0; i<5; ++i) /*both processes do this*/
{
mynum=i + '0';
sleep(1); /*5 times each*/
write(1, buffer, sizeof(buffer));
write(1, &mynum, 1);
write(1, "\n", 1);
}
return 0;
}
else
{
strcpy(buffer, "PARENT"); /*in the parent process*/
for (i=0; i<5; ++i) /*both processes do this*/
{
sleep(1); /*5 times each*/
write(1, buffer, sizeof(buffer));
write(1, &mynum, 1);
write(1, "\n", 1);
}
return 0;
}
}
Notice that mynum is a global variable.
Child is incrementing the ASCII value of mynum
Parent is not
Child and Parent can take turns running
Why does child print CHILD0, CHILD1, CHILD2, etc whereas parent prints
PARENT0, PARENT0, PARENT0, etc? Remember mynum is a global variable.