Problem 11.1
============

What is the output of the following program?

#include "csapp.h"

int main()
{
    int fd1, fd2;
    fd1 = Open("foo.txt", O_RDONLY, 0);
    Close(fd1);
    fd2 = Open("baz.txt", O_RDONLY, 0);
    printf("fd2 = %d\n", fd2);
    exit(0);
}

Problem 11.2
============

Suppose that the disk file "foobar.txt" consists of the 6 ASCII characters "foobar". Then what is the output of the following program?

#include "csapp.h"

int main()
{
    int fd1, fd2;
    char c;
    fd1 = Open("foobar.txt", O_RDONLY, 0);
    fd2 = Open("foobar.txt", O_RDONLY, 0);
    Read(fd1, &c, 1);
    Read(fd2, &c, 1);
    printf("c = %c\n", c);
    exit(0);
}

Problem 11.3
============

As before, suppose the disk file foobar.txt consists of 6 ASCII characters "foobar". Then what is the output of the following program?

#include "csapp.h"

int main()
{
    int fd;
    char c;
    fd = Open("foobar.txt", O_RDONLY, 0);
    if(Fork() == 0) {
        Read(fd, &c, 1);
        exit(0);
    }
    Wait(NULL);
    Read(fd, &c, 1);
    printf("c = %c\n", c);
    exit(0);
}

Problem 11.5
============

Assuming that the disk file foobar.txt consists of 6 ASCII characters "foobar". Then what is the output of the following program?

#include "csapp.h"

int main()
{
    int fd1, fd2;
    char c;
    fd1 = Open("foobar.txt", O_RDONLY, 0);
    fd2 = Open("foobar.txt", O_RDONLY, 0);
    Read(fd2, &c, 1);
    Dup2(fd2, fd1);
    Read(fd1, &c, 1);
    printf("c = %c\n", c);
    exit(0);
}