Question: ***THIS NEEDS TO BE DONE IN ONLY C LANGUAGE ********** Assignment: Create process creation hierarchy as a dynamic array of length n which references the
***THIS NEEDS TO BE DONE IN ONLY C LANGUAGE **********
Assignment:
Create process creation hierarchy as a dynamic array of length n which references the process control blocks (PCBs), indexed 0 to n-1
Each PCB is a structure consisting of two fields:
- parent: a PCB index corresponding to the process' creator
- children: a pointer to a linked list, where each node contains the PCB index of one child process and a link to the next child in the list
The necessary functions are simplified as follows:
create() represents the create function, which prompts for the parent process PCB[p]. The function creates a new child process PCB[q] of process PCB[p] by performing the following tasks:
- allocate a free PCB[q]
- record the parent's index, p, in PCB[q]
- initialize the list of children of PCB[q] as empty (NULL)
- create new link containing the child's index q and append the link to the linked list of PCB[p]
destroy() represents the destroy function, which prompts for the parent process PCB[p]. The function recursively destroys all descendent processes (child, grandchild, etc.) of process PCB[p] by performing the following tasks: for each element q on the linked list of children of PCB[p]:
- destroy(q) /* recursively destroy all descendants */
- free PCB[q]
- deallocate the element q from the linked list
**********THIS IS DEFAULT TEMPLATE NEED TO CODING NEXT TO EACH COMMENTS******
#include
#include
/* Define structures and global variables, including
linked list type And PCB type */
/***************************************************************/
void "OPTION 1"() {
/* declare local vars */
/* prompt for maximum number of processes */
/* allocate memory for dynamic array of PCBs */
/* Define PCB[0] */
/* Intitialize all other indices' parent to -1 */
return;
}
/***************************************************************/
void "OPTION 2"() {
/* define local vars */
/* prompt for parent process index */
/* search for next unused process q (parent=-1), using while loop */
/* allocate memory for new child PCB[q], set process index and initilize link to NULL */
/* record the parent's index p in PCB[q] */
/* initialize the list of children of PCB[q] as empty (NULL) */
/* create new link containing the child's index q and
appends the link to the end of the linked list of PCB[p] */
/* print message: cr[p] creates nth child of PCB[p] at PCB[q] */
return;
}
/***************************************************************/
void "OPTION #3--RECURSION PROCEDURE"(takes as parameter a variable of linked list type) {
/* declare local vars */
/* if node parameter passed is NULL, return */
/* else recursively call this procedure on node's link field */
/* set q to node's process field */
/* recursively call this procedure on pcb[q]'s children field */
/* print message of PCB[q] deleted */
/* free memory allocated by the node parameter */
/* set pcb[q]'s parent to -1 */
/* set node paramter to NULL */
return;
}
/***************************************************************/
void "OPTION #3"() {
/* delcare local vars */
/* prompt for parent process p */
/* print message of descendants to be destroyed */
/* call OPTION 3 recursive procedure on pcb[p]'s children */
/* set pcb[p]'s children to NULL */
return;
}
/***************************************************************/
void "OPTION #4"() {
/* if pcb is not NULL */
/* if pcb[0]'s children is not NULL */
/* call OPTION #3 recursive procedure on pcb[0]' children */
/* free memory allocated for pcb */
return;
}
/***************************************************************/
int main() {
/*declare local vars */
/* until user quits, print menu, prompt for user's choice, call appropriate procedure */
return 1;
}
Sample test run:
Process creation and destruction -------------------------------- 1) Enter parameters 2) Create a new child process 3) Destroy all descendants of a process 4) Quit program and free memory Enter selection: 1 Enter maximum number of processes: 5 Process creation and destruction -------------------------------- 1) Enter parameters 2) Create a new child process 3) Destroy all descendants of a process 4) Quit program and free memory Enter selection: 2 Enter the parent process index: 0 cr[0] /*creates 1st child of PCB[0] at PCB[1]*/ Process creation and destruction -------------------------------- 1) Enter parameters 2) Create a new child process 3) Destroy all descendants of a process 4) Quit program and free memory Enter selection: 2 Enter the parent process index: 0 cr[0] /*creates 2nd child of PCB[0] at PCB[2]*/ Process creation and destruction -------------------------------- 1) Enter parameters 2) Create a new child process 3) Destroy all descendants of a process 4) Quit program and free memory Enter selection: 2 Enter the parent process index: 2 cr[2] /*creates 1st child of PCB[2] at PCB[3]*/ Process creation and destruction -------------------------------- 1) Enter parameters 2) Create a new child process 3) Destroy all descendants of a process 4) Quit program and free memory Enter selection: 2 Enter the parent process index: 0 cr[0] /*creates 3rd child of PCB[0] at PCB[4]*/ Process creation and destruction -------------------------------- 1) Enter parameters 2) Create a new child process 3) Destroy all descendants of a process 4) Quit program and free memory Enter selection: 3 Enter the process whose descendants are to be destroyed: 0 de[0] /* destroys all descendants of PCB[0] which includes: PCB[4] PCB[3] PCB[2] PCB[1] */ Process creation and destruction -------------------------------- 1) Enter parameters 2) Create a new child process 3) Destroy all descendants of a process 4) Quit program and free memory Enter selection: 4 Quitting program
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