rand() работает не так как нужно

#include <stdio.h>
#include <iostream>
#include <time.h>
 
#include <windows.h>
using namespace std;
 
DWORD WINAPI work(LPVOID iNum);
CRITICAL_SECTION cs;
int count=0;
 
struct data
{
    float mass[9];
    float res;
    void copy(float a[])
    {
        for(int i=0;i<9;i++)
            mass[i]=a[i];
    }
};
 
data* ThreadData;
 
int main(  )
{   
   FILE *stream;  
   InitializeCriticalSection(&cs);
   if( (stream = fopen( "in.txt", "r" )) == NULL )
   {
      cout<<"Main file not found\n";
   }
   int count=0;
   fscanf(stream,"%d",&count);
   char dummy;
   fscanf(stream,"%c",&dummy);
 
   char** names;
   if(count!=0)
   {
        names=new char*[count];
        for(int i=0;i<count;i++)
        {           
            names[i]=new char[200];
            fgets( names[i], 200, stream  );            
            names[i][strlen(names[i])-1]=0;     
        }           
   }
   else
   {
        cout<<"0 files\n";
        system("PAUSE");
        return 2;
   }   
   fclose( stream );
 
   ThreadData=new data[count];
 
   EnterCriticalSection(&cs);
   for(int i=0;i<count;i++)
   {
        stream=fopen( names[i],"r");
        if(stream==NULL)
        {
            cout<<"File "<< names[i]<<" not found\n";
            system("PAUSE");
            return 1;
        }
        float mass[9];
        for (int j = 0; j < 9; j++)
        {
            fscanf(stream, "%f", &mass[j]);      
        }
        ThreadData[i].copy(mass);
        fclose(stream);
    }
   LeaveCriticalSection(&cs);
    for(int i=0;i<count;++i)            
        delete [] names[i]; 
    delete[] names;
    HANDLE*     hThread=new HANDLE[count];
    DWORD*  IDThread=new DWORD[count];
    for(int i=0;i<count;i++)
        hThread[i] = CreateThread(NULL, 0, work, (void*)i, 0, &IDThread[i]);
    Sleep(500);
    
    for(int i=0;i<count;i++)
    {
        
        for(int level=0;level<5;level++)
        {
            if(GetThreadPriority(hThread[i])==THREAD_PRIORITY_IDLE&&level==0)
                ResumeThread(hThread[i]);
            else if(GetThreadPriority(hThread[i])==THREAD_PRIORITY_LOWEST&&level==1)
                ResumeThread(hThread[i]);
            else if(GetThreadPriority(hThread[i])==THREAD_PRIORITY_BELOW_NORMAL&&level==2)
                ResumeThread(hThread[i]);
            else if(GetThreadPriority(hThread[i])==THREAD_PRIORITY_NORMAL&&level==3)
                ResumeThread(hThread[i]);
            else if(GetThreadPriority(hThread[i])==THREAD_PRIORITY_ABOVE_NORMAL&&level==3)
                ResumeThread(hThread[i]);
        }
    }
    if (WaitForMultipleObjects(count, hThread, TRUE, INFINITE) == WAIT_FAILED)
    {
        cout << "Wait for multiple objects failed." << endl;
        cout << "Input any char to exit." << endl;
        system("PAUSE");        
    }
    
    for(int i=0;i<count;i++)
        CloseHandle(hThread[i]);
    
    DeleteCriticalSection(&cs);
    
    for(int i=0;i<count;i++)
        cout<<"File "<<(i+1)<<" result: "<<ThreadData[i].res<<endl;
    delete [] ThreadData;
 
   system("PAUSE");
   return 0;
}
 
DWORD WINAPI work(LPVOID arg)
{
    EnterCriticalSection (&cs);
    count++;
    char IncBuffer[3];  
    itoa(count,IncBuffer,10);       
    char IncOut[10]="title ";
    strcat(IncOut,IncBuffer);
    system(IncOut); 
    LeaveCriticalSection(&cs);
    HANDLE hThread = GetCurrentThread();
    srand(time(0));                                                                 
    int choise=rand()%5;                                         //тут рандом
    switch(choise)
    {
    case 0: SetThreadPriority(hThread, THREAD_PRIORITY_IDLE);cout<<choise<<endl;break;
    case 1: SetThreadPriority(hThread, THREAD_PRIORITY_LOWEST);cout<<choise<<endl;break;
    case 2: SetThreadPriority(hThread, THREAD_PRIORITY_BELOW_NORMAL);cout<<choise<<endl;break;
    case 3: SetThreadPriority(hThread, THREAD_PRIORITY_NORMAL);cout<<choise<<endl;break;
    case 4: SetThreadPriority(hThread, THREAD_PRIORITY_ABOVE_NORMAL);cout<<choise<<endl;break;
    }   
    
    int num = (int)(arg);
    SuspendThread(hThread);   
    EnterCriticalSection (&cs); 
    ThreadData[num].res = ThreadData[num].mass[0] * ThreadData[num].mass[4] * ThreadData[num].mass[8] +
        ThreadData[num].mass[2] * ThreadData[num].mass[3] * ThreadData[num].mass[7] + 
        ThreadData[num].mass[1] * ThreadData[num].mass[5] * ThreadData[num].mass[6] -
        ThreadData[num].mass[2] * ThreadData[num].mass[4] * ThreadData[num].mass[6] -
        ThreadData[num].mass[1] * ThreadData[num].mass[3] * ThreadData[num].mass[8] -
        ThreadData[num].mass[0] * ThreadData[num].mass[5] * ThreadData[num].mass[7];
    count--;
    char DecBuffer[3];  
    itoa(count,DecBuffer,10);       
    char DecOut[10]="title ";
    strcat(DecOut,DecBuffer);
    system(DecOut);
    LeaveCriticalSection(&cs);
 
    return 0;
}
}

srand(unsigned(time(NULL)))