FCFS 模拟器 我想我的 pop 功能不起作用？
FCFS simulator I think my pop function is not working?
这是我的 C 代码。我正在尝试模拟 FCFS 调度程序。通过读取命令行参数，我创建了一个计时器来模拟时间。每次它增加时，我都会检查进程是否到达（使用数组），如果到达了，我将其放入 LinkedList 中以表示就绪队列。同样，每次计时器增加时，它都会检查进程是否已完成，如果已完成，则将其从链表的前面弹出。这就是我的问题所在。它错误地弹出它。
我正在使用 ./a.out input.dat text.txt 5 0.4 作为我的测试执行。这是我的 input.dat：
1 1 10 50
2 2 0 40
3 3 20 50
4 4 7 35
5 5 10 50
6 6 0 40
7 7 20 50
8 9 7 35
9 10 10 50
10 12 0 40
这是我的代码：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define n 10
char *cRR;//get the argument for RR time
char *calpha;//get the argument for alpha
int termination[n];
int full[40];
int arraylength;
int RR;//to hold RR time as an int
int i=0;//used to count amount of numbers in test file
double alpha;//hold alpha time as a double
int at[n];
typedef int LL_pid; // the pid of the PCB
typedef int LL_AT;//the arrival time of the pcb
typedef int LL_priority;//the priority of that PCB
typedef int LL_BT;//the Burst time of that PCB
typedef int LL_termination;
typedef struct LL PCB; //the PCB
struct LL //linked list structure(pcb)
{
LL_pid pid;
LL_AT AT;
LL_priority priority;
LL_BT BT;
LL_termination termination;
PCB *next;//points to next pcb in linked list
};
struct job//used for job queue
{
int pid2;
int AT2;
int priority2;
int BT2;
};
int LL_length(PCB *pcb_head); //linked list length
void LL_add(PCB **pcb_head,LL_pid ppid, LL_AT AAT, LL_priority ppriority, LL_BT BBT, LL_termination ttermination); //adds PCB to front of list
void LL_pop(PCB **pcb_head); //removes the head from the list & returns its value
void LL_print(PCB **pcb_head); //prints all the processes
void LL_clear(PCB **pcb_head); //deletes all the processes from queue
void LL_append(PCB **pcb_head,LL_pid ppid, LL_AT AAT, LL_priority ppriority, LL_BT BBT,LL_termination ttermination); //adds a process to the end of the list
int LL_elem(PCB **pcb_head, LL_pid d); //checks for the pcb via pid
void add_jobs(int jobss[]);
struct job jobs[n];//contains all the jobs an array
void find_AT(struct job jobss[],int length);
void fcfs();
void terminationfcfs();
void checktermination(PCB **pcb_head, int i);
int main ( int argc, char *argv[] )
{
PCB *pcb_head=NULL;
//*****START COMMAND LINE ARGS
if ( argc != 5 )//if they incorrectly inputed arguments
{
/* We print argv[0] assuming it is the program name */
printf( "usage: %s filename, output file name, RR quantum as a int, Alpha value as a float", argv[0] );
}
else
{
cRR=argv[3];//get arg for RR time
calpha=argv[4];//get arg for alpha
alpha=atof(calpha);//convert alpha to float
RR=atoi(cRR);//convert RR to int
// We assume argv[1] is a filename to open
FILE *file = fopen( argv[1], "r" );//open file which is 2nd arg
// fopen returns 0, the NULL pointer, on failure
if ( file == 0 )
{
printf( "Could not open file\n" );
} else
{
int y=0;//used for while loop below
while ( fscanf(file,"%d",&y)!=EOF )//scan file and find all the numbers
{
full[i]=y;//insert the numbers into an array
i++;
}
fclose( file );//done using the file
}
/*TEST PRINTING EVERYTHING IN FILE
int testprint=0;
for(testprint=0;testprint<i;testprint++){printf("%d\n",full[testprint]);}
printf("\nend of array check");*/
//write to file
FILE *fp;
fp = fopen(argv[2], "w+");
fprintf(fp, "This is testing for fprintf...\n");
fclose(fp);
}
/////////////////END OF COMMAND ARGUMENT THINGS
add_jobs(full);//adds all inputs from file to the array "jobs"
//START OF FCFS
int timer=0;
int locator = 0;
terminationfcfs();//get all termination times
for(timer=0;timer<100;timer++){
printf("Time %d : ", timer);
checktermination(&pcb_head,timer);
for(locator=0;locator<10;locator++){//every second checks each 10 values if it is their term(using linked list) or arrival time using array.
//IF ARRIVAL TIME ADD TO LINKED LIST THIS IS WORKING 5-25 2:14, same as print, something wrong with check termination
if (jobs[locator].AT2==timer){
LL_append(&pcb_head,jobs[locator].pid2,jobs[locator].AT2,jobs[locator].priority2,jobs[locator].BT2,termination[locator]);
}
}
LL_print(&pcb_head);//this works
}//END OF FCFS
//LL_print(&pcb_head);
/*test find at
add_jobs(full);
find_AT(jobs,10);
int f=0;
while(f<10){printf("%d ", at[f]); f++;}
*/
/*TEST IF ADD JOBS WORKS)
add_jobs(full);
int f=0;
while(f<10){
printf("%d " , jobs[f].pid2);
printf("%d " , jobs[f].AT2);
printf("%d " , jobs[f].priority2);
printf("%d " , jobs[f].BT2);
printf("\n");
f++;
}*/
/*testing popping array info into linked list
jobs[0].pid2=5;
jobs[0].AT2=4;
jobs[0].priority2=3;
jobs[0].BT2=2;
LL_append(&pcb_head, jobs[0].pid2,jobs[0].AT2,jobs[0].priority2,jobs[0].BT2);
LL_print(&pcb_head);
*/
/*
//example usage:
LL_add(&pcb_head, 7,7,7,7,10); //push value 7 onto stack
printf("%d\n", pcb_head -> pid); //show stack head value
LL_add(&pcb_head, 21,21,21,21,31); //push value 21 onto stack
LL_print(&pcb_head); //print the stack
if(LL_elem(&pcb_head, 7)) puts("found 7"); //does 7 belong to the stack?
LL_append(&pcb_head, 0,0,0,0,50); //append 0 to the end of the stack
LL_print(&pcb_head); //print the stack
LL_pop(&pcb_head); //pop the stack's head
LL_print(&pcb_head); //print the stack
LL_clear(&pcb_head); //clear the stack
LL_print(&pcb_head); //print the stack
*/
getchar();
return 0;
}
int LL_length(PCB *pcb_head)
{
PCB *curr = pcb_head;//set a temp value to the head
int len = 0;
while(curr)
{
++len;//increase length variable
curr = curr -> next;//go to next and keep looping to get whole length
}
return len;
}
void LL_add(PCB **pcb_head,LL_pid ppid, LL_AT AAT, LL_priority ppriority, LL_BT BBT, LL_termination ttermination)
{
PCB *pcb_new = malloc(sizeof(PCB));//allocate memory for another structure (PCB)
pcb_new -> pid = ppid;//create a pcb with pid inserted
pcb_new -> AT = AAT;
pcb_new -> priority = ppriority;
pcb_new -> BT = BBT;
pcb_new -> termination = ttermination;
pcb_new -> next = *pcb_head;//set its next to the head(inserting in front of list)
*pcb_head = pcb_new;//set the pointer of head to it since it is in front of list now
}
void LL_pop(PCB **pcb_head)
{
PCB *pcb_temp = *pcb_head;
printf("Process %d is terminating", pcb_temp->pid);
*pcb_head = pcb_temp -> next;//get the next in list and set it to head
}
void LL_print(PCB **pcb_head)
{
PCB *pcb_temp = *pcb_head;
if(!pcb_temp)
puts("the list is empty");
else
{
// while(pcb_temp)
//{
printf("Process %d is executing...", pcb_temp -> pid);// print all the pids
// printf("%d ", pcb_temp -> AT);
// printf("%d ", pcb_temp -> priority);
// printf("%d ", pcb_temp -> BT);
//pcb_temp = pcb_temp -> next;//loop to next pcb*/
//}
putchar('\n');
}
}
void LL_clear(PCB **pcb_head)
{
while(*pcb_head)//this will get every pcb as pop below sets head value to next after deleting it
LL_pop(pcb_head);
}
void LL_append(PCB **pcb_head,LL_pid ppid, LL_AT AAT, LL_priority ppriority, LL_BT BBT, LL_termination ttermination)
{
PCB *pcb_temp = *pcb_head;//get head value
if(!pcb_temp)//if nothing in head value just add the pcb as list is empty
LL_add(pcb_head, ppid, AAT, ppriority, BBT, ttermination);
else
{
while(pcb_temp -> next)//get the last pcb
pcb_temp = pcb_temp -> next;
LL_add(&(pcb_temp -> next), ppid, AAT, ppriority, BBT, ttermination);//add it onto the last
}
}
void add_jobs(int jobss[]){
int i = 0;
int i2 = 1;
int i3 = 2;
int i4 = 3;
int x =0;
int x2=0;
int x3=0;
int x4=0;
while(x<10){
jobs[x].pid2=jobss[i];
x++;
i+=4;
}
while(x2<10){
jobs[x2].AT2=jobss[i2];
i2+=4;
x2++;
}
while(x3<10){
jobs[x3].priority2=jobss[i3];
i3+=4;
x3++;
}
while(x4<10){
jobs[x4].BT2=jobss[i4];
i4+=4;
x4++;
}
arraylength=x4;
}
void find_AT(struct job jobss[], int length){
int i=0;
for(i=0;i<length;i++){
if(jobss[i].BT2>0)
at[i]=jobss[i].AT2;
}
}
void terminationfcfs(){
//find termination
int h =1;
int storage;
storage= jobs[0].AT2+jobs[0].BT2;
termination[0]=storage;
while(h<10){
storage=storage+jobs[h].BT2;
termination[h]=storage;
h++;
}
}
void checktermination(PCB **pcb_head, int i){
PCB *pcb_temp = *pcb_head;//get head
while(pcb_temp){
if(pcb_temp->termination==i)
LL_pop(&pcb_temp);
else pcb_temp=pcb_temp->next;
}
}
int LL_elem(PCB **pcb_head, LL_pid x)
{
PCB *pcb_temp = *pcb_head;//get head
while(pcb_temp)
{
if(pcb_temp -> pid == x) //set for numbers, modifiable
return 1;
else
pcb_temp = pcb_temp -> next;
}
return 0;
}
你的错误不是 LL_pop 本身，这没关系，除了你应该在弹出后释放节点内存：
void LL_pop(PCB **pcb_head)
{
PCB *pcb_temp = *pcb_head;
printf("Process %d is terminating\n", pcb_temp->pid);
*pcb_head = pcb_temp -> next;
free(pcb_temp);
}
（记住每个 malloc 应该有其对应的 free。当推送分配时，弹出应该释放分配的资源。）
错误出现在检查终止的例程中，您在其中调用 LL_pop:
LL_pop(&pcb_temp);
在这里，您传递一个局部变量的地址。更新本地指针将更新迭代器指针，但不会更新列表的头部或任何 next 指针。
不使用临时本地指针并使用指向作为头传入的指针的指针进行迭代。这将添加一个间接级别。指向指针的指针应该保存第一个节点的头指针地址或后续节点的 next 指针的地址。它将始终保存指向当前节点的指针地址，因此将更新正确的 "incoming" link:
void checktermination(PCB **pcb_head, int i)
{
while (*pcb_head){
if((*pcb_head)->termination == i) {
LL_pop(pcb_head);
} else {
pcb_head = &(*pcb_head)->next;
}
}
}
这是我的 C 代码。我正在尝试模拟 FCFS 调度程序。通过读取命令行参数，我创建了一个计时器来模拟时间。每次它增加时，我都会检查进程是否到达（使用数组），如果到达了，我将其放入 LinkedList 中以表示就绪队列。同样，每次计时器增加时，它都会检查进程是否已完成，如果已完成，则将其从链表的前面弹出。这就是我的问题所在。它错误地弹出它。
我正在使用 ./a.out input.dat text.txt 5 0.4 作为我的测试执行。这是我的 input.dat：
1 1 10 50
2 2 0 40
3 3 20 50
4 4 7 35
5 5 10 50
6 6 0 40
7 7 20 50
8 9 7 35
9 10 10 50
10 12 0 40
这是我的代码：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define n 10
char *cRR;//get the argument for RR time
char *calpha;//get the argument for alpha
int termination[n];
int full[40];
int arraylength;
int RR;//to hold RR time as an int
int i=0;//used to count amount of numbers in test file
double alpha;//hold alpha time as a double
int at[n];
typedef int LL_pid; // the pid of the PCB
typedef int LL_AT;//the arrival time of the pcb
typedef int LL_priority;//the priority of that PCB
typedef int LL_BT;//the Burst time of that PCB
typedef int LL_termination;
typedef struct LL PCB; //the PCB
struct LL //linked list structure(pcb)
{
LL_pid pid;
LL_AT AT;
LL_priority priority;
LL_BT BT;
LL_termination termination;
PCB *next;//points to next pcb in linked list
};
struct job//used for job queue
{
int pid2;
int AT2;
int priority2;
int BT2;
};
int LL_length(PCB *pcb_head); //linked list length
void LL_add(PCB **pcb_head,LL_pid ppid, LL_AT AAT, LL_priority ppriority, LL_BT BBT, LL_termination ttermination); //adds PCB to front of list
void LL_pop(PCB **pcb_head); //removes the head from the list & returns its value
void LL_print(PCB **pcb_head); //prints all the processes
void LL_clear(PCB **pcb_head); //deletes all the processes from queue
void LL_append(PCB **pcb_head,LL_pid ppid, LL_AT AAT, LL_priority ppriority, LL_BT BBT,LL_termination ttermination); //adds a process to the end of the list
int LL_elem(PCB **pcb_head, LL_pid d); //checks for the pcb via pid
void add_jobs(int jobss[]);
struct job jobs[n];//contains all the jobs an array
void find_AT(struct job jobss[],int length);
void fcfs();
void terminationfcfs();
void checktermination(PCB **pcb_head, int i);
int main ( int argc, char *argv[] )
{
PCB *pcb_head=NULL;
//*****START COMMAND LINE ARGS
if ( argc != 5 )//if they incorrectly inputed arguments
{
/* We print argv[0] assuming it is the program name */
printf( "usage: %s filename, output file name, RR quantum as a int, Alpha value as a float", argv[0] );
}
else
{
cRR=argv[3];//get arg for RR time
calpha=argv[4];//get arg for alpha
alpha=atof(calpha);//convert alpha to float
RR=atoi(cRR);//convert RR to int
// We assume argv[1] is a filename to open
FILE *file = fopen( argv[1], "r" );//open file which is 2nd arg
// fopen returns 0, the NULL pointer, on failure
if ( file == 0 )
{
printf( "Could not open file\n" );
} else
{
int y=0;//used for while loop below
while ( fscanf(file,"%d",&y)!=EOF )//scan file and find all the numbers
{
full[i]=y;//insert the numbers into an array
i++;
}
fclose( file );//done using the file
}
/*TEST PRINTING EVERYTHING IN FILE
int testprint=0;
for(testprint=0;testprint<i;testprint++){printf("%d\n",full[testprint]);}
printf("\nend of array check");*/
//write to file
FILE *fp;
fp = fopen(argv[2], "w+");
fprintf(fp, "This is testing for fprintf...\n");
fclose(fp);
}
/////////////////END OF COMMAND ARGUMENT THINGS
add_jobs(full);//adds all inputs from file to the array "jobs"
//START OF FCFS
int timer=0;
int locator = 0;
terminationfcfs();//get all termination times
for(timer=0;timer<100;timer++){
printf("Time %d : ", timer);
checktermination(&pcb_head,timer);
for(locator=0;locator<10;locator++){//every second checks each 10 values if it is their term(using linked list) or arrival time using array.
//IF ARRIVAL TIME ADD TO LINKED LIST THIS IS WORKING 5-25 2:14, same as print, something wrong with check termination
if (jobs[locator].AT2==timer){
LL_append(&pcb_head,jobs[locator].pid2,jobs[locator].AT2,jobs[locator].priority2,jobs[locator].BT2,termination[locator]);
}
}
LL_print(&pcb_head);//this works
}//END OF FCFS
//LL_print(&pcb_head);
/*test find at
add_jobs(full);
find_AT(jobs,10);
int f=0;
while(f<10){printf("%d ", at[f]); f++;}
*/
/*TEST IF ADD JOBS WORKS)
add_jobs(full);
int f=0;
while(f<10){
printf("%d " , jobs[f].pid2);
printf("%d " , jobs[f].AT2);
printf("%d " , jobs[f].priority2);
printf("%d " , jobs[f].BT2);
printf("\n");
f++;
}*/
/*testing popping array info into linked list
jobs[0].pid2=5;
jobs[0].AT2=4;
jobs[0].priority2=3;
jobs[0].BT2=2;
LL_append(&pcb_head, jobs[0].pid2,jobs[0].AT2,jobs[0].priority2,jobs[0].BT2);
LL_print(&pcb_head);
*/
/*
//example usage:
LL_add(&pcb_head, 7,7,7,7,10); //push value 7 onto stack
printf("%d\n", pcb_head -> pid); //show stack head value
LL_add(&pcb_head, 21,21,21,21,31); //push value 21 onto stack
LL_print(&pcb_head); //print the stack
if(LL_elem(&pcb_head, 7)) puts("found 7"); //does 7 belong to the stack?
LL_append(&pcb_head, 0,0,0,0,50); //append 0 to the end of the stack
LL_print(&pcb_head); //print the stack
LL_pop(&pcb_head); //pop the stack's head
LL_print(&pcb_head); //print the stack
LL_clear(&pcb_head); //clear the stack
LL_print(&pcb_head); //print the stack
*/
getchar();
return 0;
}
int LL_length(PCB *pcb_head)
{
PCB *curr = pcb_head;//set a temp value to the head
int len = 0;
while(curr)
{
++len;//increase length variable
curr = curr -> next;//go to next and keep looping to get whole length
}
return len;
}
void LL_add(PCB **pcb_head,LL_pid ppid, LL_AT AAT, LL_priority ppriority, LL_BT BBT, LL_termination ttermination)
{
PCB *pcb_new = malloc(sizeof(PCB));//allocate memory for another structure (PCB)
pcb_new -> pid = ppid;//create a pcb with pid inserted
pcb_new -> AT = AAT;
pcb_new -> priority = ppriority;
pcb_new -> BT = BBT;
pcb_new -> termination = ttermination;
pcb_new -> next = *pcb_head;//set its next to the head(inserting in front of list)
*pcb_head = pcb_new;//set the pointer of head to it since it is in front of list now
}
void LL_pop(PCB **pcb_head)
{
PCB *pcb_temp = *pcb_head;
printf("Process %d is terminating", pcb_temp->pid);
*pcb_head = pcb_temp -> next;//get the next in list and set it to head
}
void LL_print(PCB **pcb_head)
{
PCB *pcb_temp = *pcb_head;
if(!pcb_temp)
puts("the list is empty");
else
{
// while(pcb_temp)
//{
printf("Process %d is executing...", pcb_temp -> pid);// print all the pids
// printf("%d ", pcb_temp -> AT);
// printf("%d ", pcb_temp -> priority);
// printf("%d ", pcb_temp -> BT);
//pcb_temp = pcb_temp -> next;//loop to next pcb*/
//}
putchar('\n');
}
}
void LL_clear(PCB **pcb_head)
{
while(*pcb_head)//this will get every pcb as pop below sets head value to next after deleting it
LL_pop(pcb_head);
}
void LL_append(PCB **pcb_head,LL_pid ppid, LL_AT AAT, LL_priority ppriority, LL_BT BBT, LL_termination ttermination)
{
PCB *pcb_temp = *pcb_head;//get head value
if(!pcb_temp)//if nothing in head value just add the pcb as list is empty
LL_add(pcb_head, ppid, AAT, ppriority, BBT, ttermination);
else
{
while(pcb_temp -> next)//get the last pcb
pcb_temp = pcb_temp -> next;
LL_add(&(pcb_temp -> next), ppid, AAT, ppriority, BBT, ttermination);//add it onto the last
}
}
void add_jobs(int jobss[]){
int i = 0;
int i2 = 1;
int i3 = 2;
int i4 = 3;
int x =0;
int x2=0;
int x3=0;
int x4=0;
while(x<10){
jobs[x].pid2=jobss[i];
x++;
i+=4;
}
while(x2<10){
jobs[x2].AT2=jobss[i2];
i2+=4;
x2++;
}
while(x3<10){
jobs[x3].priority2=jobss[i3];
i3+=4;
x3++;
}
while(x4<10){
jobs[x4].BT2=jobss[i4];
i4+=4;
x4++;
}
arraylength=x4;
}
void find_AT(struct job jobss[], int length){
int i=0;
for(i=0;i<length;i++){
if(jobss[i].BT2>0)
at[i]=jobss[i].AT2;
}
}
void terminationfcfs(){
//find termination
int h =1;
int storage;
storage= jobs[0].AT2+jobs[0].BT2;
termination[0]=storage;
while(h<10){
storage=storage+jobs[h].BT2;
termination[h]=storage;
h++;
}
}
void checktermination(PCB **pcb_head, int i){
PCB *pcb_temp = *pcb_head;//get head
while(pcb_temp){
if(pcb_temp->termination==i)
LL_pop(&pcb_temp);
else pcb_temp=pcb_temp->next;
}
}
int LL_elem(PCB **pcb_head, LL_pid x)
{
PCB *pcb_temp = *pcb_head;//get head
while(pcb_temp)
{
if(pcb_temp -> pid == x) //set for numbers, modifiable
return 1;
else
pcb_temp = pcb_temp -> next;
}
return 0;
}
你的错误不是 LL_pop 本身，这没关系，除了你应该在弹出后释放节点内存：
void LL_pop(PCB **pcb_head)
{
PCB *pcb_temp = *pcb_head;
printf("Process %d is terminating\n", pcb_temp->pid);
*pcb_head = pcb_temp -> next;
free(pcb_temp);
}
（记住每个 malloc 应该有其对应的 free。当推送分配时，弹出应该释放分配的资源。）
错误出现在检查终止的例程中，您在其中调用 LL_pop:
LL_pop(&pcb_temp);
在这里，您传递一个局部变量的地址。更新本地指针将更新迭代器指针，但不会更新列表的头部或任何 next 指针。
不使用临时本地指针并使用指向作为头传入的指针的指针进行迭代。这将添加一个间接级别。指向指针的指针应该保存第一个节点的头指针地址或后续节点的 next 指针的地址。它将始终保存指向当前节点的指针地址，因此将更新正确的 "incoming" link:
void checktermination(PCB **pcb_head, int i)
{
while (*pcb_head){
if((*pcb_head)->termination == i) {
LL_pop(pcb_head);
} else {
pcb_head = &(*pcb_head)->next;
}
}
}