controlling two threads

I'm programming in C and using Visual Studio++. The question is about the following code:
How can I stop the second thread within the first thread ?

I don't know if this is the right way to solve the problem, my knowledge about threads is...poor.

Thanks

Code:

---

#include <stdio.h>
#include <windows.h>
#include <conio.h>
#include <time.h>
#include <process.h>


HANDLE hStdIn, hStdOut; /* standard input, output handles */

void gotoxy (int col, int fil);

// second thread
void crono(int *par);

// first thread
void main(void)
{

    int n;
   
    int fil = 0;
    HANDLE handle;

    printf("\t Thread\n");
        printf("\t_________\n");

    handle = (HANDLE) _beginthread( crono,0,&fil); // create thread
   
        for(n=0;n<10;n++)
        {
                gotoxy(0,n+2);
                printf("\ndoes it runs ???");
                fflush(stdin);
                getch();
                /*-----------------------------------------*/
                /* if(n==5) I WANT TO STOP THE 2ND THREAD */
                /*-----------------------------------------*/
        }
        printf("\n\n\nNYAM !!!\t");

 }

/***********************************************************************/

void crono(int *par)
{
        time_t ti,tf;
        int i,temps;

        time(&ti);

        do
        {
                //if(*param==5) _endthread;
                gotoxy(10,15);
                time(&tf);
                temps=tf-ti;
                printf("\r%d",temps);
                for(i=0;i<90000;i++);
               
        }while(temps<10);

    _endthread();

}
/************************************************************/

void gotoxy (int col, int fil)
{
        COORD coord;
        HANDLE hStdout; /* get variable handler for screen*/
        hStdout = GetStdHandle(STD_OUTPUT_HANDLE); /* assign screen handler*/

        coord.X = col; coord.Y = fil;
        SetConsoleCursorPosition (hStdout, coord);
}

/***********************************************************************/

---

Synchronisation start here.

Wow, void main and fflush(stdin)
Time to read the FAQs

Ok, Ok... :D Homework done !

Thanks !