如何在奇偶排序程序中正確創建線程和排序？

我正在嘗試使用多線程實現c中的奇偶轉置排序算法。該程序將收到一個文件，其中包含需要正確排序的一行整數。我已經創建了該程序將使用的數組，並且正在正確讀取數據。雖然，我不太清楚如何正確創建線程。我知道我需要的線程數量總是N/2。然而N不會總是20，所以我現在處理的是有限的數量。這是一個限制，雖然B/C N不會總是20.它可能會更高。我的程序現在只能處理二十個。即使我已經有一個名爲swap的函數，我也遇到了排序部分的問題。起點功能就是這一切發生的地方。我不確定該問題的起始位置。如何在奇偶排序程序中正確創建線程和排序？

這是我到目前爲止的代碼：

#include <stdio.h> 
#include <stdlib.h> 
#include <unistd.h> 
#include <pthread.h> 

int list[20]; 
int n = 20; 
int param[10]; 

pthread_t threads[10]; 

void readLINE(char *filename); 
void do_swap(int R1, int R2); 
void display(); 
void *startPoint(void *arg); 


void readLINE(char *filename) 
{ 
    FILE* file; 
    int i,j; 
    file = fopen(filename,"r"); 
    if(file==NULL) 
    { 
     printf("Error: can't open file.\n"); 
} 
else 
{ 
    printf("File opened successfully.\n"); 

    i = 0; 
    while(!feof(file)) 
    { 
     fscanf(file,"%d", &list[i]); 
     i++; 
    } 

    printf("The numbers are: \n"); 
    for(j=0; j< i-1; j++) 
    { 
     printf("%d\n", list[j]); 
    } 

    fclose(file); 
} 

n = i-1; 

} 

//swap positions of arguments in list array 
void swap(int R1, int R2) 
{ 
if (list[R1] > list[R1+1]) 
{ 
    int temp = list[R1]; 
    list[R1] = list[R2]; 
    list[R2] = temp; 
} 
} 

void display() 

{ 
    int count; 
    for (count = 0; count < n; count++) 

    { 
     //cout << list[count] << " " ; 
     printf("%d ",list[count]); 
    } 
    //cout << endl; 
    printf("\n"); 
} 

void *startPoint(void *arg) 
{ 

int R1 = *(int*)arg; 

int count; 
for (count = 0; count < n/2; count++) 
{ 

} 
return 0; 
} 

int main(int argc, char** argv) 
{ 
pthread_attr_t tattr; 

pthread_attr_init (&tattr); 
pthread_attr_setscope(&tattr, PTHREAD_SCOPE_SYSTEM); 


readLINE(argv[1]); 
printf("list[] presorted:"); 
display(); 

//create n/2 threads to do the sorting algorithm 
//the parameter to each thread is an int: 
//first thread param is 0 
//second thread param is 2 
//third thread param is 4 etc.... 
int count; 
for (count = 0; count < n/2; count++) 
{ 
    param[count] = count*2; 
    pthread_create(&threads[ count], NULL, startPoint, (void*) &param[count]); 
} 

//wait for all the reads to finish before exiting the program 
//otherwise the process would exit and abort all the threads 

for (count = 0; count < n/2; count++) 
{ 
    pthread_join(threads[count], NULL); 
} 

//display the sorted state of the list 
printf("list[] after sorting: "); 
display(); 

exit(0); 
}

來源

2010-03-10 saltinyellow