nothing different happened to the variables? What was the point in that?

ex1/ex1.c

@@ -10,5 +10,19 @@ int main(void)
 {
     // Your code here
 
+    pid_t pid = fork();
+
+    if (pid == 0)
+    {
+        int x = 200;
+        printf("\n This is the child, x = %d\n", x);
+        exit(1);
+    }
+    else
+    {
+        int x = 100;
+        printf("\n This is the parent, x = %d\n", x);
+    }
+
     return 0;
 }

ex2/ex2.c

@@ -1,5 +1,5 @@
-// Write a program that opens the text.txt file (with the `fopen()` library call) located in this directory 
-// and then calls `fork()` to create a new process. Can both the child and parent access the file descriptor 
+// Write a program that opens the text.txt file (with the `fopen()` library call) located in this directory
+// and then calls `fork()` to create a new process. Can both the child and parent access the file descriptor
 // returned by `fopen()`? What happens when they are written to the file concurrently?
 
 #include <stdio.h>
@@ -8,7 +8,23 @@
 
 int main(void)
 {
-    // Your code here 
-
+    // Your code here
+    pid_t pid = fork();
+    FILE *fp;
+    fp = fopen("text.txt", "w+");
+
+    if (pid == 0)
+    {
+
+        fprintf(fp, "\n I\'m printing from the child\n");
+        exit(1);
+    }
+    else
+    {
+        fprintf(fp, "\n I\'m printing from the parent\n");
+    }
+
     return 0;
 }
+
+// oddly enough only the child printed in my code.. did I do something wrong?

ex2/text.txt

@@ -0,0 +1,3 @@
+
+ I'm printing from the child
+

ex3/ex3.c

@@ -10,6 +10,18 @@
 int main(void)
 {
     // Your code here
+    pid_t pid = fork();
+
+    if (pid == 0)
+    {
+        printf("\nHello\n");
+        exit(1);
+    }
+    else
+    {
+        wait(NULL);
+        printf("\nGoodbye\n");
+    }
 
     return 0;
 }

ex4/ex4.c

@@ -11,6 +11,20 @@
 int main(void)
 {
     // Your code here    
+    pid_t pid = fork();
+
+    if (pid == 0) {
+        // execlp("ls", "ls", NULL);
+        char *cmd = "ls";
+        char *argv[3];
+        argv[0] = "ls";
+        argv[1] = "-la";
+        argv[2] = NULL;
 
+        execvp(cmd, argv); //This will run "ls -la" as if it were a command
+    } else {
+        wait(NULL);
+        printf("Child process has ended\n");
+    }
     return 0;
 }

ex5/ex5.c

@@ -10,13 +10,38 @@
 
 #define MSGSIZE 16
 
-char* msg1 = "hello world #1";
-char* msg2 = "hello world #2";
-char* msg3 = "hello world #3";
+char* msg1 = "hello world #1\n";
+char* msg2 = "hello world #2\n";
+char* msg3 = "hello world #3\n";
 
 int main(void)
 {
     // Your code here
+    int fd[2]; // init pipe array
+    pipe(fd); // init the pipe
+
+    pid_t pid = fork(); // init the fork
+
+
+    char* messages[sizeof MSGSIZE];
+    int buf[128];
+        messages[0] = msg1;
+        messages[1] = msg2;
+        messages[2] = msg3;        
+
+    if (pid < 0) {
+        perror("fork failed\n");
+        exit(1);
+    } else if (pid == 0) {
+        write(fd[1], messages[0], sizeof messages[0]);
+        write(fd[1], messages[1], sizeof messages[1]);
+        write(fd[1], messages[2], sizeof messages[2]);
+    } else {
+        wait(NULL);
+        read(fd[0], messages[0], sizeof buf);
+        read(fd[0], messages[1], sizeof buf);
+        read(fd[0], messages[2], sizeof buf);
+    }
 
     return 0;
 }