c - Round Robin C 调度模拟器

Question

我正在为 C 中的 Round Robin 调度算法制作一个模拟器。现在我做的时间片是 2。所以每 2 秒它从列表的前面开始一个“进程”，减少它的剩余时间2，然后将其粘贴到列表的末尾并获取下一个。此外，每一秒，它都会将其他人的等待时间增加 1。但是，当我尝试在函数 round_Robin()，它删除它。但它不会将其附加到链表的末尾。我究竟做错了什么？谢谢你!我这样使用命令行参数:

./a.out input.dat text.txt 5 0.4

这是我的input.dat:

1 0 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 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];

int global_timer=-1;


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_remainingtime;
typedef int LL_wT;
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_remainingtime RT;
    LL_wT wT;
    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_remainingtime RRT,LL_wT wTT); //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_remainingtime RRT,LL_wT wTT); //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 counter(PCB **pcb_head);
void round_Robin(PCB **pcb_head);


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"
counter(&pcb_head);
round_Robin(&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_remainingtime RRT, LL_wT wTT)
{
    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 -> RT = RRT;
    pcb_new -> wT = wTT;
    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("\nProcess %d is terminating\n", pcb_temp->pid);
    *pcb_head = pcb_temp -> next;
    free(pcb_temp);
}





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 has terminated...", 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_remainingtime RRT,LL_wT wTT)
{
    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, RRT, wTT);
    else
    {
        while(pcb_temp -> next)//get the last pcb
            pcb_temp = pcb_temp -> next;

        LL_add(&(pcb_temp -> next), ppid, AAT, ppriority, BBT, RRT, wTT);//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;

}



//NEED TO CHANGE 2 TO THE REAL ROUND BOBIN QUANTUM, NEED TO ADD IF RT IS LESS THEN QUANTUM, THEN PRINT FOR RT
void round_Robin(PCB **pcb_head){
PCB *pcb_temp = *pcb_head;
PCB *next = (*pcb_head)->next;//get the next value since it will be the next head
int x;
//store all the heads values
int storepid = pcb_temp->pid;
int storeat = pcb_temp->AT;
int storepriority=pcb_temp->priority;
int storebt=pcb_temp->BT;
int storert=pcb_temp->RT;
int storewt=pcb_temp->wT;


for (x=0;x<100;x++){
    if(*pcb_head){
        int h=0;
            for(h=0;h<2;h++){//2 is represented as the time quantum right now
            printf("\nProcess %d is running", (*pcb_head)->pid);
            counter(pcb_head);//even tho this increases wt we already stored original wt in storewt

            }
        LL_pop(pcb_head);//get rid of it from head
        storert-=2;//its remaining time decreases
        LL_append(&next,storepid,storeat,storepriority,storebt,storert,storewt);//append it to the list

        }
        else{
    printf("....");
    counter(pcb_head);}//run counter and see if any new processes

}



}

void counter(PCB **pcb_head){
int locator;
PCB *pcb_temp = *pcb_head;
global_timer++;//increase the time
printf("\nTIME %d:", global_timer);
        for(locator=0;locator<10;locator++){
            if (jobs[locator].AT2==global_timer){//see if any processes are ready to enter the ready queue linked list
                LL_append(pcb_head,jobs[locator].pid2,jobs[locator].AT2,jobs[locator].priority2,jobs[locator].BT2,jobs[locator].BT2,0); }           
            }
while(pcb_temp){
pcb_temp-> wT +=1;//increase everyones waiting time in the linked list ready queue
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;
}

编辑:

#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 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];

int global_timer=-1;


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_remainingtime;
typedef int LL_wT;
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_remainingtime RT;
    LL_wT wT;
    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_remainingtime RRT,LL_wT wTT); //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_remainingtime RRT,LL_wT wTT); //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 counter(PCB **pcb_head);
void round_Robin(PCB **pcb_head);


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"
counter(&pcb_head);
round_Robin(&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_remainingtime RRT, LL_wT wTT)
{
    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 -> RT = RRT;
    pcb_new -> wT = wTT;
    pcb_new -> next = NULL;//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("\nProcess %d is terminating\n", pcb_temp->pid);
    *pcb_head = pcb_temp -> next;
    free(pcb_temp);
}





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 has terminated...", 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_remainingtime RRT,LL_wT wTT)
{
    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, RRT, wTT);
    else
    {
        while(pcb_temp -> next)//get the last pcb
            pcb_temp = pcb_temp -> next;

        LL_add(&(pcb_temp -> next), ppid, AAT, ppriority, BBT, RRT, wTT);//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;

}



//NEED TO CHANGE 2 TO THE REAL ROUND BOBIN QUANTUM, NEED TO ADD IF RT IS LESS THEN QUANTUM, THEN PRINT FOR RT
void round_Robin(PCB **pcb_head){
int x;
for (x=0;x<250;x++){
PCB *pcb_temp = *pcb_head;
PCB *next = (*pcb_head)->next;//get the next value since it will be the next head
int storepid = pcb_temp->pid;
int storeat = pcb_temp->AT;
int storepriority=pcb_temp->priority;
int storebt=pcb_temp->BT;
int storert=pcb_temp->RT;
int storewt=pcb_temp->wT;
    if(*pcb_head){//if there is something in the list
        int h=0;
            if(storert>=2){//if the remaining time is greater than the quantum
                for(h=0;h<2;h++){//2 is represented as the time quantum right now
                    printf("\nProcess %d is running", (*pcb_head)->pid);
                    counter(pcb_head);//even tho this increases wt we already stored original wt in storewt
                    //print it for the quantum
                }
                LL_pop(pcb_head);//get rid of it from head
                storert-=2;//its remaining time decreases by the quantum
                if(storert>0){//if it still has remaining time append it
                    LL_append(&next,storepid,storeat,storepriority,storebt,storert,storewt);}//append it to the list}
                else{printf("Process has finished");}//if it doesnt type it finished
            }
            else{//if the remaining time is less then the quantum
                for(h=0;h<storert;h++){//do it for how much is remaining
                    printf("\nProcess %d is running", (*pcb_head)->pid);
                    counter(pcb_head);
                }   
            LL_pop(pcb_head);//get rid of it from head because it finished
            printf("Process has finished");     
            }
        }
    else{
    printf("....");
    counter(pcb_head);}//run counter and see if any new processes

}



}

void counter(PCB **pcb_head){
int locator;
PCB *pcb_temp = *pcb_head;
global_timer++;//increase the time
printf("\nTIME %d:", global_timer);
        for(locator=0;locator<10;locator++){
            if (jobs[locator].AT2==global_timer){//see if any processes are ready to enter the ready queue linked list
                LL_append(pcb_head,jobs[locator].pid2,jobs[locator].AT2,jobs[locator].priority2,jobs[locator].BT2,jobs[locator].BT2,0); }           
            }
while(pcb_temp){
pcb_temp-> wT +=1;//increase everyones waiting time in the linked list ready queue
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;
}

Answer 1

这段代码:

PCB *pcb_temp = *pcb_head;
PCB *next = (*pcb_head)->next;//get the next value since it will be the next head
//store all the heads values
int storepid = pcb_temp->pid;
int storeat = pcb_temp->AT;
int storepriority=pcb_temp->priority;
int storebt=pcb_temp->BT;
int storert=pcb_temp->RT;
int storewt=pcb_temp->wT;

需要在每个循环中完成，而不仅仅是在循环之前完成一次。否则，您将继续将相同的项目附加到末尾，而不是当前的头项目。

此外，LL_add() 不能用于追加到列表，因为它总是假定它是添加到头部:

pcb_new -> next = *pcb_head;
*pcb_head = pcb_new;

如果要追加到尾部，则需要如下代码:

pcb_new -> next = NULL;
*tail_ptr = pcb_new;

编辑:

LL_add() 似乎只用于附加到尾部而不是头部。在这种情况下，只需更改这一行:

pcb_new -> next = *pcb_head;

为此:

pcb_new -> next = NULL;

但是，如果您确实进行了此更改，则不要尝试使用此修改后的版本插入到头部，因为它不会起作用。