// A demonstration of unix pipes where the output of the parent

// A demonstration of unix pipes where the output of the parent
// program is redirected to the input of a child
#include <iostream>
#include <unistd.h>

using namespace std;

void parent_main();
void child_main();

int main(void) {
int p[2];
int i;
int pid;

//create the pipe
pipe(p);

//fork the process
pid = fork();

//set up the pipe
if(pid) {
//parent process does the writing
dup2(p[1], STDOUT_FILENO);

//close the unused side of the pipe
close(p[0]);

parent_main();
} else {
//child process does the reading
dup2(p[0], STDIN_FILENO);

//close the unused side of the pipe
close(p[1]);

child_main();
}

return 0;
}

void
parent_main() {
for(int i=0; i<10; i++) {
cout << i << endl;
}
}

void
child_main() {
//read the entire input stream
int i;
while(cin >> i) {
cout << "Child received: " << i << endl;
}

}