fork mulitple child in one parent - c++

Question

I want to fork three child process in one parent.
And the following is my C++ code:
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <iostream>
using namespace std;
int main()
{
pid_t pid;
for (int i = 0; i < 3; i++)
{
pid = fork();
if (pid < 0)
{
cout << "Fork Error";
return -1;
}
else if (pid == 0)
cout << "Child " << getpid() << endl;
else
{
wait(NULL);
cout << "Parent " << getpid() << endl;
return 0;
}
}
}
Now my output is :
Child 27463
Child 27464
Child 27465
Parent 27464
Parent 27463
Parent 27462
How should I modify my program to get the output like the following?
Child 27463
Child 27464
Child 27465
Parent 27462
What I mean is that these THREE children need to belong to the same ONE parent, can anybody give me some suggestion ?
Thank you all. :)

Answer 1

You should exit the execution of the child processes. Otherwise, they continue forking also
pid_t pid;
for(i = 0; i < 3; i++) {
pid = fork();
if(pid < 0) {
printf("Error");
exit(1);
} else if (pid == 0) {
cout << "Child " << getpid() << endl;
exit(0);
} else {
wait(NULL);
cout << "Parent " << getpid() << endl;
}
}

Answer 2

There are two issues:
children zero and one continue with the for loop, spawning further processes;
the "parent" branch terminates instead of continuing with the loop.
The following will produce the output you want:
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <iostream>
using namespace std;
int main()
{
pid_t pid;
for (int i = 0; i < 3; i++)
{
pid = fork();
if (pid < 0)
{
cout << "Fork Error";
return -1;
}
else if (pid == 0) {
cout << "Child " << getpid() << endl;
return 0;
} else {
wait(NULL);
if (i == 2) {
cout << "Parent " << getpid() << endl;
}
}
}
}
When I run it, I get
Child 4490
Child 4491
Child 4492
Parent 4489

Answer 3

Move your return 0 from the last condition to the middle one:
if (pid < 0)
{
cout << "Fork Error";
return -1;
}
else if (pid == 0) {
cout << "Child " << getpid() << endl;
return 0;
}
else
{
wait(NULL);
cout << "Parent " << getpid() << endl;
}
This way the parent will continue to loop, and the children will terminate instead of looping.