我跟你剛好相反
我寫的程式都沒有架構化
麻花捲型的程式碼

看看合不合用

#include <math.h>
#include <iostream>
using namespace std;

class Quadratic{
public:
Quadratic(double _a, double _b, double _c){
a=_a;
b=_b;
c=_c;
};
void solver();
//一元二次方程式公式解解出方程式
void print();
// print() print the answers in the form m+ni,
//where m is the real part and n is the imaginary part

private:
	double a;
	double b;
	double c;
	double real, imag;
	int flag;
	double real_1, imag_1;
	double real_2, imag_2;
};

void Quadratic::solver(){
double ans;
int j;
double m,n;
ans=b*b-4*a*c;
if(ans<0)
ans=abs(ans);
ans=pow(ans,0.5);
for(int i;i<(b*b);i++){
if(ans==(i*i))
j=j+1;
}
flag = j;
if(j==0){
    //std::cout<<-b<<"_"<<ans/(2*a)<<endl;
    real_1 = -1 * b;
    imag_1 = ans / (2*a);
}
else{
    m=(-b+ans)/(2*a);
    // cout<<m<<"_0"<<endl;
    real_1 = m;
    imag_1 = 0;
    n=(-b-ans)/(2*a);
    // cout<<n<<"_0"<<endl;
    real_2 = n;
    imag_2 = 0;
}
    print();
}

void Quadratic::print(){
    if (flag==0) {
        cout << real_1 << "+" << imag_1 << "i" << endl;
    } else {
        cout << real_1 << "+" << imag_1 << "i" << endl;
        cout << real_2 << "+" << imag_2 << "i" << endl;
    }
}

//我不知道如何把solver的cout移動到print()裡

int main(){
double a, b, c;
cout<<"input a,b,c";
cin >> a >> b >> c;
Quadratic formula(a, b, c);
formula.solver();
return 0;
}
//main檔不可以動

好像沒規定一定要移到print中,
如果真的要這樣做,
不如把Quadratic class新增一個解答的變數,
解題的時候先把答案紀錄在變數中,
print的時候直接將變數列印出來.