Parent Process in Windows Lab1

parent.c

#include<stdio.h>
#include<Windows.h>

#define NO_OF_PROCESS 4

int main(int argc, char* argv[])
{
  STARTUPINFO si[NO_OF_PROCESS];  //needed info to create process, cb(size needed for info), new window, title... 
  PROCESS_INFORMATION pi[NO_OF_PROCESS]; //to store info of newly created process, ids, handles of process and thread...
  int i=0;
  //Whatcha planning after creating processes, putting them on a leash, so they won't run away. You are reading my mind.
  //Joke besides, in order to manage process after creation, you need to create a handle for it.
  HANDLE handle[NO_OF_PROCESS];

  //need to clear memory for startup info struct, 
  //because if there is any value left, it may mess process that's gonna be created.

  for(i=0; i<NO_OF_PROCESS; i++) 
  {
    //ZeroMemory sometimes can be ignored while compiling so we use SecureZeroMemory.
    //Cleaning memory starting from the beginning of the startup info struct
    SecureZeroMemory(&si[i], sizeof(STARTUPINFO));
    si[i].cb = sizeof(STARTUPINFO);
    //Cleaning memory starting from the beginning of the process info struct
    SecureZeroMemory(&pi[i], sizeof(PROCESS_INFORMATION));
    
  }
  //This array keeps arguments that we are going to use while creating our child processes.
  //Our parent process will execute those items as a command line in terminal
  //First one is the process(program) that is gonna be executed and second is the first argument to this process.
  char *lpCommandLine[] = {"child.exe 1", "child.exe 2", "child.exe 3", "child.exe 4"};


  //Are we readyyyyyy? to create our child processes? Yessssssssss!
  //There are lots of parameters that CreateProces func. takes. 
  //Let's focus on lpCommandLine, si, pi and flag for a new window(new window for each process) for now.
  if(!CreateProcess(NULL, lpCommandLine[i], NULL, NULL, FALSE, CREATE_NEW_WINDOW, NULL, NULL, &si[i], &pi[i]))
  {
    printf("No process and cookies for you!");
    system("pause");
    exit(0);
  }

  else
  {
    printf("parent is working just fine.");
    handles[i] = pi[i].hProcess; //let's get handle of newly created process from process info
  }
   
  //After parent finishes creating child processes, it wants to call it a day. 
  //But not that easy parent, be a responsible parent and wait for your all children.
  WaitForMultipleObjects(NO_OF_PROCESS, handles, INFINITE); //how many?, where is the leash?, how much to wait?

  //Okey, we are done. done is done. time to let go of those leashes so others who need can use later.
  //Let's close our handles. We have two of them for each process. 
  //Each process is created with at least one thread which is called primary thread. 
  //This thread also has a handle. Don't believe me? Examine the process info struct;)
  for(i=0; i<NO_OF_PROCESS; i++) 
  {
   CloseHandle(pi[i].hProcess); //or CloseHandle(handle[i])
   CloseHandle(pi[i].hThread);  
  }

  return 1;
}