C ++错误:没有匹配的调用函数 [英] C++ Error: no matching function for call
问题描述
我正在尝试使用对分法求解二次方程。尝试求根时,出现以下错误:没有匹配的调用函数。
I am trying to solve a quadratic equation using the bisection method. When trying to evaluate the roots I get this error: "no matching function for call".
#include "assign4.h"
#include <iostream>
using namespace std;
int main(int argc, char * argv[]){
solution s;
double root;
cout << "Enter interval endpoints: ";
cin >> s.xLeft >> s.xRight;
cout << "Enter tolerance: ";
cin >> s.epsilon;
root = s.bisect (s.xLeft, s.xRight, s.epsilon, s.f, s.error);
if (!(s.error))
cout << "Root found at " << root << "\nValue of f(x) at root is: " << s.f(root);
else
cout << "The solution of a quadratic equation with coefficients: " << endl;
cout << "a = " << a << ", b = " << b << ", c = " << c << endl;
cout << "has not been found." << endl;
return 0;
}
错误发生在root = ...似乎有问题我的功能是f但我不明白这是怎么回事。以下两段代码是我的类和类实现文件。我们刚刚开始使用类,因此不确定我的问题是否在上面或仅在上面的代码中。
The error occurs where root = ... it seems to have a problem with my function f but I don't understand what is wrong. The following two bits of code are my class and class implementation files. We just started working with classes so I am uncertain if my problem lies there or simply in the above code.
#ifndef ASSIGN4_H
#define ASSIGN4_H
class solution {
public:
double xLeft, xRight;
double epsilon;
bool error;
double bisect(double, double, double, double f(double), bool&);
double f(double);
};
#endif // ASSIGN4_H
///////////// ///////////////////////////////////////////////////// ///////////////////////////////////////////////////// /////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#include "assign4.h"
#include <iostream>
#include <cmath>
using namespace std;
double solution::bisect (double xLeft, double xRight, double epsilon, double func(double), bool& error) {
double xMid;
double fLeft, fRight;
double fMid;
fLeft = f(xLeft);
fRight = f(xRight);
error = (fLeft * fRight) > 0;
if (error)
return -999.0;
while (fabs (xLeft - xRight) > epsilon) {
xMid = (xLeft + xRight) / 2.0;
fMid = f (xMid);
if (fMid == 0.0)
return xMid;
else if (fLeft * fMid < 0.0)
xRight = xMid;
else
xLeft = xMid;
cout << "New Interval is [" << xLeft << ", " << xRight << "]" << endl;
}
return (xLeft + xRight) / 2.0;
}
double solution::f (double x) {
return ((5 * pow(x,2.0)) + (5 * x) + 3);
}
推荐答案
如果要使用指针
Change
double bisect(double, double, double, double f(double), bool&);
到
double bisect(double, double, double, double (solution::*f)(double), bool&);
在声明和定义中。
更改来自
root = s.bisect (s.xLeft, s.xRight, s.epsilon, s.f, s.error);
到
root = s.bisect (s.xLeft, s.xRight, s.epsilon, &solution::f, s.error);
这就是我为我成功编译并链接的东西。
This is what I have that compiles and links successfully for me.
#include <iostream>
#include <typeinfo>
#include <math.h>
using namespace std;
class solution {
public:
double xLeft, xRight;
double epsilon;
bool error;
double bisect(double, double, double, double (solution::*f)(double), bool&);
double f(double);
};
using namespace std;
double solution::bisect (double xLeft, double xRight, double epsilon, double (solution::*func)(double), bool& error) {
double xMid;
double fLeft, fRight;
double fMid;
fLeft = (this->*func)(xLeft);
fRight = (this->*func)(xRight);
error = (fLeft * fRight) > 0;
if (error)
return -999.0;
while (fabs (xLeft - xRight) > epsilon) {
xMid = (xLeft + xRight) / 2.0;
fMid = (this->*func)(xMid);
if (fMid == 0.0)
return xMid;
else if (fLeft * fMid < 0.0)
{
xRight = xMid;
fRight = fMid;
}
else
{
xLeft = xMid;
fLeft = fMid;
}
cout << "New Interval is [" << xLeft << ", " << xRight << "]" << endl;
}
return (xLeft + xRight) / 2.0;
}
double solution::f (double x) {
return ((5 * pow(x,2.0)) + (5 * x) + 3);
}
int main(int argc, char * argv[]){
solution s;
double root;
cout << "Enter interval endpoints: ";
cin >> s.xLeft >> s.xRight;
cout << "Enter tolerance: ";
cin >> s.epsilon;
root = s.bisect (s.xLeft, s.xRight, s.epsilon, &solution::f, s.error);
if (!(s.error))
cout << "Root found at " << root << "\nValue of f(x) at root is: " << s.f(root) << endl;
else
{
cout << "The solution of a quadratic equation with coefficients: " << endl;
// cout << "a = " << a << ", b = " << b << ", c = " << c << endl;
cout << "has not been found." << endl;
}
return 0;
}
这篇关于C ++错误:没有匹配的调用函数的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!