多线程中printf与输入输出流的区别？该如何解决

int g_cnt;
unsignedint _stdcall ThreadProc1(PVOID lpParameter)
{
         g_cnt++;
        printf("subThreadis running! g_cnt = %d\n",g_cnt);
//       cout << "subThread is running!g_cnt = " << g_cnt << endl; //此处和printf打印在多线程操作中的区别？
         return 0;
}
 
int main()
{
    g_cnt = 0;
         const int nThreadNum = 5;
         HANDLE hThread1[nThreadNum];
         //Caution...!
         for( int i=0; i < nThreadNum; i++)
         {
                   hThread1[i]=(HANDLE)_beginthreadex(NULL,0,ThreadProc1,NULL,0,NULL);
         }      
         WaitForMultipleObjects(nThreadNum,hThread1,true,INFINITE);
 
         _endthreadex(0);
         return 0;
 
}