Question

Можете расписать действия в коде

#include
#include
using namespace std;

class calc
{
protected:
int sum;
void action(int a, string sign, int b)
{
if(sign == "+")
sum = a + b;
if(sign == "*")
sum = a * b;
if(sign == "-")
sum = a - b;
if(sign == "%")
sum = a % b;
}
};

class ex : public calc
{
protected:
int a, b;
string sign;
public:
void signal_1(int a)
{
this->a = a;
}
void signal_2(string sign)
{
this->sign = sign;
}
void signal_3(int b)
{
this->b = b;
action(a, sign, b);
signal_4();
}
void signal_4()
{
outt();
this-> a = sum;
}
void outt()
{
cout << a << ' '<< sign << ' ' << b << " = "<< sum;
}
};

string take_symb(string s, int &i)
{
string buf;

buf = "";
i = 0;
while (s[i] != ' ')
{
buf += s[i];
i++;
}
return buf;
}

int main(void)
{
string s;
ex exp;
int i = 0;
getline(cin, s);

exp.signal_1(stoi(take_symb(s, i)));
s.erase(0, i + 1);
while (s.length() > 0)
{
exp.signal_2(take_symb(s, i));
s.erase(0, i + 1);
exp.signal_3(stoi(take_symb(s, i)));
s.erase(0, i + 1);
if (s != "")
cout << endl;
}
return 0;
}