Some task

#include <iostream>
#include <cmath>

#define ESP 1e-6

using namespace std;

class comp {
    float Re, Im;

    public:
        comp() {}

        comp& operator = (const comp &x) {
            Re = x.Re;
            Im = x.Im;
            return *this;
        }
        comp& operator -= (const comp &x) {
            Re -= x.Re;
            Im -= x.Im;
            return *this;
        }

        friend comp operator + (const comp &a, const comp &b);

        bool operator == (const comp &x) {
            return(this -> Re == x.Re && this -> Im == x.Im);
        }

        void set(char s) {
            cout<<"Enter comp numb "<<s<<":"<<endl;
            cout<<"\tRe: ";
            cin>>Re;
            cout<<"\tIm: ";
            cin>>Im;
            return;
        }

        void get(char s);
};
int main () {
    comp a, b, c;
    a.set('a');
    b.set('b');

    cout<<"operator -="<<endl;
    cout<<"before"<<endl;
    a.get('a');
    b.get('b');
    cout<<"after"<<endl;
    a -= b;
    a.get('a');
    b.get('b');

    cout<<"operator +"<<endl;

    a.get('a');
    b.get('b');

    c = a + b;

    cout<<"c = a + b :"<<endl;
    c.get('c');

    cout<<"operator == "<<endl;
    a.get('a');
    b.get('b');

    cout<<"a == b"<<endl;
    if(a == b) {
        cout<<"true";
    } else {
        cout<<"false";
    }

    a = b;

    cout<<"  a assigned b :"<<endl;

    cout<<"operator =="<<endl;
    a.get('a');
    b.get('b');

    cout<<"a == b"<<endl;
    if(a == b) {
        cout<<"true";
    } else {
        cout<<"false";
    }
    return 0;
}
comp operator + (const comp &a, const comp &b) {
    comp c;
    c.Re = a.Re + b.Re;
    c.Im = a.Im + b.Im;
    return c;
}

bool zero(double x) {
    return fabs(x) <= ESP; //було так return fabs(x) > ESP;
}
void comp :: get(char s) {
    cout <<"comp numb "<<s<<": ";
    if(!zero(Re)) {
        cout<<Re;
    }
    if(!zero(Im)) {
        if(!zero(Im) && Im > 0) {
            cout<<" + ";
        }
        if(Im < 0) {
            cout<<" - ";
        }
        cout << abs(Im)<<"i";
    }
    cout <<endl;
    return;
}