Using C program for thread synchronization to print numbers in sequence

Given a thread, the program must print the threads from 0 to 10 according to their priority.

What is a thread?

Threads are lightweight processes that run inside the program. A simple program can contain n threads.

Unlike Java, the C/C language standard does not support multi-threading. POSIX threads (Pthreads) are the standard for multi-threading in C/C. The C language does not contain any built-in support for multi-threaded applications, but relies entirely on the operating system to provide this functionality. How does

work in our program?

In order to use thread functions, we use the header file #include. This header file will contain all thread-related functions in our program, such as pthread_create(), etc.

The current task is to use the pthread standard library provided by the gcc compiler to synchronize n threads. The idea is to get the thread count and print 1 in the first thread, 2 in the second thread, 3 in the third thread, until the tenth thread. The output will contain numbers from 1 to 10 based on the thread's priority. The Chinese translation of

Algorithm

Start
Step 1 -> Declare global variables as int MAX=10 and count=1
Step 2 -> declare variable thr of pthread_mutex_t and cond of pthread_cond_t
Step 3 -> Declare Function void *even(void *arg)
   Loop While(count < MAX)
      Call pthread_mutex_lock(&thr)
      Loop While(count % 2 != 0)
         Call pthread_cond_wait(&cond, &thr)
      End
      Print count++
      Call pthread_mutex_unlock(&thr)
      Call pthread_cond_signal(&cond)
   End
   Call pthread_exit(0)
Step 4 -> Declare Function void *odd(void *arg)
   Loop While(count < MAX)
      Call pthread_mutex_lock(&thr)
      Loop While(count % 2 != 1)
         Call pthread_cond_wait(&cond, &thr)
      End
      Print count++
      Call pthread_mutex_unlock(&thr)
      Call pthread_cond_signal(&cond)
   End
   Set pthread_exit(0)
Step 5 -> In main()
   Create pthread_t thread1 and pthread_t thread2
   Call pthread_mutex_init(&thr, 0)
   Call pthread_cond_init(&cond, 0)
   Call pthread_create(&thread1, 0, &even, NULL)
   Call pthread_create(&thread2, 0, &odd, NULL)
   Call pthread_join(thread1, 0)
   Call pthread_join(thread2, 0)
   Call pthread_mutex_destroy(&thr)
   Call pthread_cond_destroy(&cond)
Stop

Example

is:

Example

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
int MAX = 10;
int count = 1;
pthread_mutex_t thr;
pthread_cond_t cond;
void *even(void *arg){
   while(count < MAX) {
      pthread_mutex_lock(&thr);
      while(count % 2 != 0) {
         pthread_cond_wait(&cond, &thr);
      }
      printf("%d ", count++);
      pthread_mutex_unlock(&thr);
      pthread_cond_signal(&cond);
   }
   pthread_exit(0);
}
void *odd(void *arg){
   while(count < MAX) {
      pthread_mutex_lock(&thr);
      while(count % 2 != 1) {
         pthread_cond_wait(&cond, &thr);
      }
      printf("%d ", count++);
      pthread_mutex_unlock(&thr);
      pthread_cond_signal(&cond);
   }
   pthread_exit(0);
}
int main(){
   pthread_t thread1;
   pthread_t thread2;
   pthread_mutex_init(&thr, 0);
   pthread_cond_init(&cond, 0);
   pthread_create(&thread1, 0, &even, NULL);
   pthread_create(&thread2, 0, &odd, NULL);
   pthread_join(thread1, 0);
   pthread_join(thread2, 0);
   pthread_mutex_destroy(&thr);
   pthread_cond_destroy(&cond);
   return 0;
}

Output

If we run the above program, it will generate The following output

1 2 3 4 5 6 7 8 9 10

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