understanding fork() ???

Hi all , this may be a weird question , but please I need your help !!!

how this C program work ?

Code:

int main() {
        int p1 , p2;
        p1 = fork();
        p2 = fork();
        printf("end\n");
}

If you instrument the code to see what is going on...

Code:

output:
Starting process:  7033
end of process: 7033
I'm a brand new process:  7034   My daddy was : 7033
I'm a brand new process:  7035   My daddy was : 7033
end of process: 7035
end of process: 7034
I'm a brand new process:  7036   My daddy was : 7034
end of process: 7036

Code:

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
void whoami(pid_t *);  /* show the process id's of the parent and the current process */

int main(int argc , char *argv[]) {            
        int p1 , p2;    
        pid_t pids[10]={0};        
        pids[0]=getpid();  /* pid of parent process */  
        printf("Starting process: %5d\n",pids[0]);
        whoami(pids);
        p1 = fork();    
        whoami(pids);
        p2 = fork();    
        whoami(pids);
        printf("end of process:%5d\n",getpid());
        return 0;
}                 
void whoami(pid_t * pids){  /* this looks to see if the process is a new one */
        pid_t this_process;
        int found=0;
        pid_t *pidptr;
        this_process=getpid();
        for(found=0,this_process=getpid(),pidptr=pids;*pidptr && !found;pidptr++)
        	 if(this_process==*pidptr) found=1;
        if(!found){
                 *pidptr=this_process;
                 printf("I'm a brand new process: %5d ",this_process);
                 printf("  My daddy was :%5d\n", getppid());
        }
      
}

thank you very much , that was a great help