Linux系统C/C++:多线程和多进程

编程解决问题：
1号进程创建2，3号两个进程
2号进程创建两个线程Thread1，Thread2
Thread1：求（1~n）之间的素数
Thread2：生成Fibonacci序列
3号进程创建4，5号两个进程
4号进程执行系统命令，ls，ps，cp等
5号进程执行一个用户编写的可执行文件
每个进程输出自己的进程ID和父进程的进程ID

/*
 * OSPro1.c
 *
 *  Created on: Nov 10, 2016
 *      Author: koala
 */


#include<stdio.h>
#include<sys/types.h>
#include<unistd.h>
#include<sys/wait.h>
#include<stdlib.h>
#include<pthread.h>

//Fibonacci sequence
void Fibonacci()
{
    int f[100]={0};
    f[0] = 0;
    f[1] = 1;
    printf("Fibonacci sequence is: ");
    int a;
    for(a=2;a<10;a++)
    {
        f[a]= f[a-1] + f[a-2];
    }
    for(a=0;a<10;a++)
        printf("%d ",f[a]);
    printf("\n");
    printf("Thread Fibonacci exit\n");
    pthread_exit(0);
}

//Primenumber sequence
void Primenumber(void*arg)
{
    int n = *(int *)arg;
    int i;
    int j;
    int flag;
    printf("Primenumber sequence is: %d ",2);
    for(i=2; i<=n; i++)
    {
        for(j=2; j<i; j++)
        {
            if(i%j == 0){
                flag =0;
                break;
            }
            flag =1;
        }
        if(flag)
            printf("%d ",i);
    }
    printf("\n");
    printf("Thread Primenumber exit\n");
    pthread_exit(0);
}


int main()
{
    pid_t pid_1, pid_2, pid_3; //Declare 3 process
    pid_1 = getpid();

    printf("Parent Pid_1 is %d\n", pid_1);

    if((pid_2 = fork()) == 0) //fork() create children process
    {
        int ret1, ret2;
        pthread_t tid1, tid2; //Declare 2 thread
        printf("Pid_2 is %d, its parent is %d\n", getpid(), getppid());
    int n=20;
        ret1 = pthread_create(&tid1, NULL, (void*)Primenumber, &n); //create thread and execute Primenumber() 

        if(ret1 == 0) 
        printf("Thread_1 ok!\n");
        else 
        printf("Thread_1 failed!\n");

        ret2 = pthread_create(&tid2, NULL, (void*)Fibonacci, NULL);//create thread and execute Fibonacci() 

        if(ret2 == 0) 
        printf("Thread_2 ok!\n");
        else 
        printf("Thread_2 failed!\n");

        pthread_join(tid1, NULL);//waitting thread1 finished
        pthread_join(tid2, NULL);//waitting thread2 finished
    }

    if((pid_3 = fork()) == 0 && getppid() == pid_1)
    {
        pid_t pid_4, pid_5;
        printf("Pid_3 is %d, its parent is %d\n", getpid(), getppid());

        if((pid_4 =fork()) == 0)
        {
            printf("Pid_4 is %d, its parent is %d\n", getpid(), getppid());
            int ret3;

            ret3 = execl("/bin/ls", "ls", "-l", NULL);

            if(ret3 < 0) 
        perror("execl error!\n");
            else printf("Successfuly execute the ls -l commond!\n");
        }

        if((pid_5 = fork()) == 0)
        {
            printf("Pid_5 is %d, its parent is %d", getpid(), getppid());
            int ret4;

            ret4 = execl("demo", "./demo", NULL);//execute demo.c (./demo)

            if(ret4 < 0) 
        perror("execl error!\n");
            else 
        printf("Successfuly execute the \"demo\"!\n");
        }

        pid_t cpid = wait(NULL);
        printf("The process 3 exit, and its child process is %d\n", cpid);
    }

    pid_t cpid = wait(NULL); //waitting children process finished
    printf("The process %d exit\n", cpid);
    exit(0);
    return 0;

}

//demo.c
#include <stdio.h>
#include <stdlib.h>

int main()
{
    printf("This is \"demo\" process !\n");
    return 0;
}

运行效果：