如何修改代码以匹配输出 Linux

Question

Code below outputs child and parents PID output however need it to look more like the sample output below. How could I modify my code to allow this to happen. Any help is greatly appreciated.

parent process: counter=1

child process: counter=1

parent process: counter=2

child process: counter=2

The code is (edited to fix missing semicolon and make more readable):

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

int main(void) {
    int pid;

    pid = fork();

    if (pid < 0)
    {
        printf("\n Error ");
        exit(1);
    }
    else if (pid == 0)
    {
        printf("\n Child Process ");
        printf("\n Pid is %d ", getpid());
        exit(0);
    }
    else
    {
        printf("\n Parent process ")
        printf("\n Pid is %d ", getpid());
        exit(1);
    }
}

Answer 1

You have a missing ; in your code, so it wouldn't compile cleanly. Also, there is no loop outputting the text that you require.

Consider instead the following:

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

int
main()
{
        pid_t pid;

        char *child  = "child";
        char *parent = "parent";
        char *me;

        pid = fork();

        if (pid < 0) {
                perror("fork()");
                exit(EXIT_FAILURE);
        } else if (pid == 0)
                me = child;
        else
                me = parent;

        for (int i = 0; i < 2; ++i)
                printf("%s: counter is %d\n", me, i + 1);

        return EXIT_SUCCESS;
}

This calls fork() and detects whether the current process is the child or the parent. Depending on which it is, we point me to the correct string and enter a short loop that just prints our string and the counter.

The output may be

parent: counter is 1
parent: counter is 2
child: counter is 1
child: counter is 2