如果没有包含quadratic.cpp文件的驱动程序，我似乎无法使用它。我把它设置为Dev C ++中的一个项目，但是继续得到错误，说明对驱动程序中调用的所有函数的未定义引用。
quadratic.h
#include <iostream>
using namespace std;
class Quadratic{
private:
float a,b,c;
public:
//Quadratic();
Quadratic();
Quadratic(float a,float b,float c);
float x;
float get_a();
float get_b();
float get_c();
float evaluate(float);
void set();
int numRoots(Quadratic &qTest);
float roots1(int numRoots, Quadratic &qRoots);
float roots2(int numRoots, Quadratic &qRoots);
};
Quadratic operator+(const Quadratic &q1,const Quadratic &q2);
Quadratic operator*(double r, const Quadratic& q);
quadratic.cpp
#include<iostream>
#include "quadratic.h"
#include <cmath> // std::sqrt(double)
using namespace std;
//Default Constructor
Quadratic::Quadratic():a(0),b(0),c(0){}
//Had to add this to get the overloaded + operator to work
//(mainly because of the way I had it return the new instance)
Quadratic::Quadratic(float aSum, float bSum, float cSum)
{
this->a = aSum;
this->b = bSum;
this->c = cSum;
}
float Quadratic::get_a()
{
return a;
}
float Quadratic::get_b()
{
return b;
}
float Quadratic::get_c()
{
return c;
}
float Quadratic::evaluate(const float x)
{
return ((a*(x*x))+(b*x)+c);
}
void Quadratic::set()
{
float aNew=0.0,bNew=0.0,cNew=0.0;
cout<<"Enter a new a: ";
cin>>aNew;
cout<<"Enter a new b: ";
cin>>bNew;
cout<<"Enter a new c: ";
cin>>cNew;
this->b = bNew;
this->c = cNew;
this->a = aNew;
}
int Quadratic::numRoots(Quadratic &qTest)
{
float a= qTest.get_a();
float b= qTest.get_b();
float c= qTest.get_c();
int numRoots=0;
if ((a==0)&&(b==0)&&(c==0))
{
//every value of x = real root, so infinity
numRoots=3;
}
else if((a==0)&&(b==0)&&(c!=0))
{
numRoots=0;
}
else if((a==0)&&(b!=0))
{
numRoots=1;
//root is x= -c/b
}
else if((a!=0)&&( (b*b)<(4*a*c) ))
{
numRoots=0;
}
else if((a!=0)&&( (b*b)==(4*a*c) ))
{
numRoots=1;
//root is x= -b/2a
}
else if((a!=0)&&( (b*b)>(4*a*c) ))
{
numRoots=2;
//root is x= +/- quadratic formula
}
return numRoots;
}
float Quadratic::roots1(int numRoots, Quadratic &qRoots)
{
float root1=0.0;
float rootPlus=0.0;
float rootMinus=0.0;
if (numRoots==1)
{
if((a==0)&&(b!=0))
{
root1 = (((0-c)/b));// + ((0-c)%b));
}
if((a!=0)&&( (b*b)==(4*a*c) ))
{
root1 = (((0-b)/(2*a)));// + ((0-b)%(2*a)));
}
}
else if (numRoots == 2)
{
rootMinus= (((0-b)-sqrt((b*b)-(4*a*c)))/(2*a));
rootPlus= (((0-b)+sqrt((b*b)-(4*a*c)))/(2*a));
if (rootMinus > rootPlus) root1=rootPlus;
else root1=rootMinus;
}
else if (numRoots == 3) root1=0;
return root1;
}
float Quadratic::roots2(int numRoots, Quadratic &qRoots)
{
float root2=0.0;
float rootPlus=0.0;
float rootMinus=0.0;
if (numRoots==1)
{
if((a==0)&&(b!=0))
{
root2 = (((0-c)/b));// + ((0-c)%b));
}
if((a!=0)&&( (b*b)==(4*a*c) ))
{
root2 = (((0-b)/(2*a)));// + ((0-b)%(2*a)));
}
}
else if (numRoots == 2)
{
rootMinus= (((0-b)-sqrt((b*b)-(4*a*c)))/(2*a));
rootPlus= (((0-b)+sqrt((b*b)-(4*a*c)))/(2*a));
if (rootMinus < rootPlus) root2=rootPlus;
else root2=rootMinus;
}
else if (numRoots == 3) root2=0;
return root2;
}
Quadratic operator+(Quadratic &q1,Quadratic &q2)
{
float tempa,tempb,tempc=0.0;
tempa= q1.get_a() + q2.get_a();
tempb= q1.get_b() + q2.get_b();
tempc= q1.get_c() + q2.get_c();
Quadratic temp(tempa, tempb,tempc);
return temp;
// return Quadratic( q1.get_a() + q2.get_a(),
// q1.get_b() + q2.get_b(),
// q1.get_c() + q2.get_c());
}
Quadratic operator*(double r, Quadratic& q)
{
return Quadratic( q.get_a() * r,
q.get_b() * r,
q.get_c() * r);
}
的main.cpp
#include<iostream>
//#include "quadratic.cpp""
#include "quadratic.h"
using namespace std;
int main()
{
//Default constructors called, all 3 coefficients set to 0
Quadratic q1;
Quadratic q2;
cout<<"Default constructor called\n"
<<"q1 a = "<<q1.get_a()<<"\n"
<<"q1 b = "<<q1.get_b()<<"\n"
<<"q1 c = "<<q1.get_c()<<"\n"
<<"q2 a = "<<q2.get_a()<<"\n"
<<"q2 b = "<<q2.get_b()<<"\n"
<<"q2 c = "<<q2.get_c()<<"\n";
//Call the set function to set all 3 coefficents of existing
//quadratic expression to new values
q1.set();
q2.set();
cout<<"\nSet function called. New values:\n"
<<"q1 a = "<<q1.get_a()<<"\n"
<<"q1 b = "<<q1.get_b()<<"\n"
<<"q1 c = "<<q1.get_c()<<"\n"
<<"q2 a = "<<q2.get_a()<<"\n"
<<"q2 b = "<<q2.get_b()<<"\n"
<<"q2 c = "<<q2.get_c()<<"\n";
//calls function to evaluate the quadratic expression for a given calue of x
cout<<"\nEnter x: ";
float x=0.0;
cin>>x;
cout<<"for q1, ax^2 + bx +c = "<<q1.evaluate(x)
<<"\nfor q2, ax^2 + bx +c = "<<q2.evaluate(x);
//add q1+q2 with overloaded + operator
Quadratic quad_sum = q1 + q2;
cout<<"\n\nAdding q1+_q2\n"
<<"\nq1_a + q2_a= "<<quad_sum.get_a()
<<"\nq1_b + q2_b= "<<quad_sum.get_b()<<" "
<<"\nq1_c + q2_c= "<<quad_sum.get_c();
//multiply the coefficients by r using overloaded * operator
cout<<"\n\nEnter a number to multiply the coefficeints by: ";
double r=0.0;
cin>>r;
Quadratic quad_prod=r*quad_sum;
cout<<"\nMultiplying q1 by r results in "
<<"\nnew a = "<<quad_prod.get_a()
<<"\nnew b = "<<quad_prod.get_b()
<<"\nnew c = "<<quad_prod.get_c();
//calculate number of and display roots
int numroots=q1.numRoots(q1);
cout<<"\n\nNumber of Roots for q1 = "<<numroots;
if (numroots != 0) cout<<"\nThey are: "<<q1.roots1(numroots, q1)<<" and "<<q1.roots2(numroots, q1);
}
已添加
#ifndef QUAD_H_
#define QUAD_H_
和
#endif
到头文件，但仍然为驱动程序中的每个函数调用获取“未定义的引用”。