changing variables within loop from outside class - class

Question

I have a time class and a Build class. The harvest function increases the minerals count for the entire time, but the nunmber of minerals depends on the number of available workers. As soon as a build starts, the number of workers decreases.
So, how can i decrease the number of workers, within the loop, and not after the loop has finished.
I want minerals to keep increasing, but the number of workers should increase and decrease based on the Build call.
class Time {
private:
int minerals = 50;
int workers = 6;
int vespene = 0;
int supply = 6;
int time = 0;
public:
Time ();
int Time_counter();
void harvest();
int mineral_count();
int worker_count();
int supply_count();
void update(int m, int w, int s, int t);
void Display();
};
Time::Time ()
{
for (int i =0; i<9; i++)
{
update(minerals, workers, supply, time);
harvest();
time = i;
// Time_counter();
}
}
int Time::Time_counter() {
return time;
}
void Time::harvest() {
minerals+= workers * (0.7);
}
int Time:: mineral_count() {
return minerals;
}
int Time::worker_count() {
//return workers.size();
return workers;
}
int Time::supply_count() {
return supply;
}
void Time:: update(int m, int w, int s, int t) {
minerals = m;
workers = w;
supply = s;
time = t;
cout << "No. of Minerals: " <<minerals <<"\n" <<"No.of Workers: " <<workers <<"\n"
<< "No. of Supply: " <<supply <<"\n" <<"Current Time: " <<time << endl;
}
void Time:: Display ()
{
cout << "No. of Minerals: " <<minerals <<"\n" <<"No.of Workers: " <<workers <<"\n"
<< "No. of Supply: " <<supply <<"\n" <<"Current Time: " <<time << endl;
}
class Build: public Time {
public:
void Build_create();
};
void Build::Build_create() {
int build_count=0;
SCV obj;
int m = obj.mineral_count();
int w = obj.worker_count();
int s = obj.supply_count();
int t; // = obj.Time_counter();
if (m >= 50 && biuld_count<2)
{
cout << "Build start....";
m-= 50;
obj.update(m,w,s,t);
obj.Display ();
w-=1;
for (t = obj.Time_counter(); t <obj.Time_counter()+ 10; t++)
{cout<< "Building...";}
cout << " Build complete" << endl;
scv_count++;
w += 1;
s += 1;
t = obj.Time_counter();
obj.update(m, w, s, t);
obj.Display ();
}
else if (m<50)
{
cout << "Cannot build " << endl;
}
else if (build_count==2)
{
cout<<"two already built.." <<endl;
}