Simple use of and Sleep(); function

#include<iostream>
#include<conio.h>
#include<windows.h>
using namespace std;
int main()
{
    unsigned int a;
    a=true;
    if(a==true){
system("color 0A");

for(int i=11;i>=0;i--)
{
        cout <<"\t\t\t\t"<<i<< endl;
        Sleep(1000);
        system("cls");
 
        if(i==3)
        {
              
                //a==false;
                cout  << "\t\t\t\tReady"<< endl;
                Sleep(1000);
                  system("cls");
                cout <<"\t\t\t\tstady" << endl;
                Sleep(1000);
                  system("cls");
                 
                cout <<"\t\t\t\tgo" <<endl;
                  system("cls");
                Sleep(1000);
                 break;
        }
}

}
getch();
return 0;
}