consider the `fork` program given, how many times does the following program print hello?

Question

Please, consider the fork program given below:

How many times does the following program print hello?

main(int argc, char **argv) {
 int i;
 for (i=0; i < 3; i++) {
 fork();
 printf("hello\n");
 }
}

Total “hello” messages = 2 + 4 + 8 = 14 (see question-1 at page-5).

---

How many times does the following program print hello?

#include <stdio.h>
#include <unistd.h>
main()
{
int i;
for (i=0; i<3; i++)
fork();
printf("hello\n");
}

Total “hello” messages = 8 (see question-4 at page-5).

It seems to me both program are same. Why are explanation/answer is different?

Can you explain, please?

Answer 1

Here printf("hello\n”); statement in first program is inside the for loop.

for (i=0; i < 3; i++) {
 fork();
 printf("hello\n”);
 }

And, printf("hello\n”); statement in second program is outside the for loop.

for (i=0; i<3; i++)
fork();//after semicolon printf is outside the for loop's block scope.
printf("hello\n");

That is difference between both given code.