How to exchange information between 1 parent process and 3 child processes with fork() on c or c++

Question

i need to make a program that can exchange the information between 1 parent and 3 child process created with fork(). The overall task is to send anything from 3-rd child process to 2-nd child and a parent one, and from 2-nd child process to 3-rd. i have the following code to create multiple child processes, but don't understand how to send anything to different processes. Can you help me with this?

for (int kid = 0; kid < 3; ++kid) {
    int pid = fork();
    if(pid < 0){
        exit(EXIT_FAILURE);
    }
    else if (pid > 0){
        /* Parent process */
    }
    else{
        /* Child process */
        exit(EXIT_SUCCESS);
    }
}

for (int kid = 0; kid < 3; ++kid) {
    int status;
    pid_t pid = wait(&status); // kids could be ready in any order
}