Added Process exercise's chapter

ex17.c

@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define SIZE 5
+
+int nums[SIZE] = {0, 1, 2, 3, 4};
+
+int main(void) {
+  int i;
+  pid_t pid;
+
+  pid = fork();
+
+  if (pid == 0) {
+    for (i = 0; i < SIZE; i++) {
+      nums[i] *= -i;
+      printf("CHILD : %d\n", nums[i]); // Linea X
+    }
+  } else if (pid > 0) {
+    wait(NULL);
+    for (i = 0; i < SIZE; i++) {
+      printf("PARENT: %d\n", nums[i]); // Linea Y
+    }
+  }
+
+  return EXIT_SUCCESS;
+}