error：overloaded'operator<<'必须是二进制运算符（有3个参数）

本文介绍了error：overloaded'operator&lt;&lt;'必须是二进制运算符（有3个参数）的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我知道有很多这样的问题，但我找不到一个适合我的解决方案。 我试图使简单分数计算器比可以添加或减去任何数量的函数，并将答案写为减少的分数。 示例：input = 3/2 + 4 / 8 ，output = 2 我尝试重载运算符以完成此操作。 我试图开发输入包括一个表达式的分数由运算符'+'或' - '分隔。 表达式中的分数数是任意的。 以下6行都是有效输入表达式的示例： 1/2 + 3/4 1/2 -5 / 7 + 3/5 355/113 3 / 9-21 / -7 4 / 7-5 / -8 -2 / -3 + 7/5 *我遇到的问题是，当我运行我的程序，它有一个重载操作错误：错误：重载的操作符<<'必须是二进制运算符（有3个参数）* /Users/Spicycurryman/Desktop/ECS40/hw1/fraction.cpp:61:22：error：overloaded 'operator'<''必须是二进制运算符（具有3个参数） ostream& Fraction :: operator<<<（ostream& os，Fraction& n） ^ /Users/Spicycurryman/Desktop/ECS40/hw1/fraction.cpp:80:22：error：overloaded'operator> ;>'必须是二进制运算符（具有3个参数） istream& Fraction :: operator>>（istream& os，Fraction& n） 了解为什么这是一个错误。 我的下列代码如下： CPP FILE b $ b #includeFraction.h Fraction :: Fraction（int a，int b） { } int Fraction :: find_gcd（int n1，int n2） { int gcd，remainder; remainder = n1％n2; while（remainder！= 0） { n1 = n2; n2 = remainder; remainder = n1％n2; } gcd = n2; return（gcd）; } void Fraction :: reduce_fraction（int nump，int denomp） { this-> nump = nump; this-> denomp = denomp; int gcd; gcd = find_gcd（nump，denomp）; nump = nump / gcd; denomp = denomp / gcd; if（（denomp< 0& amp; nump< 0）） { denomp * = - 1; nump * = - 1; } else if（denomp< 0& amp; nump> 0）{ denomp * = - 1; } if（denomp == 0）{ throw invalid_argument（Error：zero denominator）; } } 分数& Fraction :: operator +（const Fraction& n）{ denom = denomp * n.denom; numera =（nump * n.numera）+（n.denom * n.nump）; return（* this）; } 分数& Fraction :: operator-（const Fraction& n）{ denom = denomp * n.denom; numera =（nump * n.numera） - （n.denom * n.nump）; return（* this）; } ostream& Fraction :: operator< { if（n.numera == 0） { cout< 0<< endl; return os; } else if（n.numera == n.denom） { cout< 1<< endl; return os; } else { cout< n.numera< '/'< n.denom< endl; return os; } } istream& Fraction :: operator>>（istream& os，Fraction& n） { char slash = 0; return os>> n.numera>>斜线>> ; } 标题文件 > #ifndef FRACTION_H #define FRACTION_H #include< iostream> #include< stdexcept> using namespace std; class Fraction { public： Fraction（int a，int b）; int fraction（int a，int b）; int find_gcd（int n1，int n2）; void reduce_fraction（int nump，int denomp）; Fraction& operator +（const Fraction& n）; Fraction& operator-（const Fraction& n）; friend ostream& operator<<（ostream& os，const Fraction& n）; friend istream& operator>>（istream& is，const Fraction& n）; private： int denom; int numera; int denomp; int nump; }; #endif MAIN CPP FILE / p> #includeFraction.h #include< iostream> using namespace std; int main（） { Fraction x（2,3）; 分数y（6，-2）; cout<< x cout<< y cin>> y; cout<< y Fraction z = x + y; cout<< x } 我知道运算符是成员函数，参数，意味着我的运算符现在需要三个参数，它可以被固定为非成员函数;然而，这不会在这个程序中工作。在我的情况下，我将如何解决它所以程序将工作？ 非常感谢！解决方案问题是作为非成员函数声明 operator>> 和运算符，但定义为成员函数。 / p> 这应该解决这个问题（但打开另一组问题）。因此，而不是 ostream& Fraction :: operator<<（ostream& os，Fraction& n） { ... istream& Fraction :: operator>>（istream& os，Fraction& n） { ... $ b b 实现为： ostream&运算符<<（ostream& os，Fraction& n） { ... istream& operator>>（istream& os，Fraction& n） { ... 此外，请注意您声明的函数为： 朋友ostream& operator<<（ostream& os，const Fraction& n）; friend istream& operator>>（istream& is，const Fraction& n）; 但定义为（因此您更改了签名）： ostream& Fraction :: operator<<（ostream& os，Fraction& n） istream& Fraction :: operator>>（istream& os，Fraction& n） 正确的方法是声明并定义为： ostream& Fraction :: operator<<（ostream& os，const Fraction& n） istream& Fraction :: operator>>（istream& os，Fraction& n） 我只是添加了更改。其余与问题相同： class Fraction { friend ostream& operator<<（ostream& os，const Fraction& n）; friend istream& operator>>（istream& is，Fraction& n）; //其余的是相同的}; ostream&运算符<<<（ostream& os，const Fraction& n） { if（n.numera == 0） { cout< 0<< endl; return os; } else if（n.numera == n.denom） { cout< 1<< endl; return os; } else { cout< n.numera< '/'< n.denom< endl; return os; } } istream&运算符>>（istream& os，Fraction& n） { char slash = 0; return os>> n.numera>>斜线>> ; } I know there are plenty of questions like these, but I couldn't find a solution that worked for me. I am trying to make simple fraction calculator than can add or subtract any number of functions and write the answer as a reduced fraction. Example: input=3/2 + 4/8, output =2I am trying overload operators in order to accomplish this.So in the program, I am trying to develop the input consists of an expression made of fractions separated by the operators '+'or '-'. The number of fractions in the expression is arbitrary. Each of the following 6 lines is an example of valid input expression:1/2 + 3/41/2 -5/7+3/5355/1133 /9-21/ -74/7-5/-8-2/-3+7/5*The problem that I am having is that in when I run my program it has a overload operating error: error: overloaded 'operator<<' must be a binary operator (has 3 parameters)* /Users/Spicycurryman/Desktop/ECS40/hw1/fraction.cpp:61:22: error: overloaded 'operator<<' must be a binary operator (has 3 parameters) ostream& Fraction::operator<<(ostream &os, Fraction& n) ^/Users/Spicycurryman/Desktop/ECS40/hw1/fraction.cpp:80:22: error: overloaded 'operator>>' must be a binary operator (has 3 parameters) istream& Fraction::operator>>(istream &os, Fraction& n)I don't understand why that is an error. My following code is below:CPP FILE#include "Fraction.h"Fraction::Fraction(int a, int b){}int Fraction::find_gcd (int n1, int n2) { int gcd, remainder; remainder = n1 % n2; while ( remainder != 0 ) { n1 = n2; n2 = remainder; remainder = n1 % n2; } gcd = n2; return (gcd);}void Fraction::reduce_fraction(int nump, int denomp) { this->nump = nump; this->denomp = denomp; int gcd; gcd = find_gcd(nump, denomp); nump = nump / gcd; denomp = denomp / gcd; if ((denomp<0 && nump < 0 )) { denomp*=-1; nump*=-1; } else if (denomp < 0 && nump >0){ denomp*=-1; } if ( denomp ==0) { throw invalid_argument( "Error: zero denominator" ); } }Fraction& Fraction::operator+(const Fraction& n) { denom = denomp * n.denom; numera = (nump * n.numera) + (n.denom * n.nump); return (*this);}Fraction& Fraction::operator-(const Fraction& n) { denom = denomp * n.denom; numera = (nump * n.numera) - (n.denom* n.nump); return (*this);} ostream& Fraction::operator<<(ostream &os, Fraction& n){ if (n.numera == 0) { cout << 0 << endl; return os; } else if (n.numera == n.denom) { cout << 1 << endl; return os; } else { cout << n.numera << '/' << n.denom << endl; return os; }} istream& Fraction::operator>>(istream &os, Fraction& n){ char slash = 0; return os >> n.numera >> slash >> n.denom;}Header File#ifndef FRACTION_H#define FRACTION_H#include <iostream>#include <stdexcept>using namespace std;class Fraction{ public: Fraction(int a, int b); int fraction(int a,int b); int find_gcd(int n1, int n2); void reduce_fraction(int nump, int denomp); Fraction& operator+(const Fraction& n); Fraction& operator-(const Fraction& n); friend ostream& operator<<(ostream &os, const Fraction& n); friend istream& operator>>(istream &is, const Fraction& n);private: int denom; int numera; int denomp; int nump;};#endifMAIN CPP FILE#include "Fraction.h"#include <iostream>using namespace std;int main(){ Fraction x(2,3); Fraction y(6,-2); cout << x << endl; cout << y << endl; cin >> y; cout << y << endl; Fraction z = x + y; cout << x << " + " << y << " = " << z << endl;}I know that the operators are member functions and a member function takes an implicit first parameter, meaning my operators now takes three parameters it may be fixed being a non-member function; however, that would not work in this program. How exactly in my case would I fix it so the program would work? Thank you very much! 解决方案 The problem is that you declared operator>> and operator<< as non-member functions, but defined as a member function.This should fix that problem (but open another set of problems). So instead of ostream& Fraction::operator<<(ostream &os, Fraction& n) { ... istream& Fraction::operator>>(istream &os, Fraction& n) { ...implement as : ostream& operator<<(ostream &os, Fraction& n){... istream& operator>>(istream &os, Fraction& n){...Also, take a note that you declared functions as :friend ostream& operator<<(ostream &os, const Fraction& n);friend istream& operator>>(istream &is, const Fraction& n);but defined as (therefore you changed the signature) : ostream& Fraction::operator<<(ostream &os, Fraction& n) istream& Fraction::operator>>(istream &os, Fraction& n)Proper way is to declare and define as : ostream& Fraction::operator<<(ostream &os, const Fraction& n) istream& Fraction::operator>>(istream &os, Fraction& n)I am adding just changes. The rest is the same as in the question:class Fraction{ friend ostream& operator<<(ostream &os, const Fraction& n); friend istream& operator>>(istream &is, Fraction& n); // the rest is the same};ostream& operator<<(ostream &os, const Fraction& n){ if (n.numera == 0) { cout << 0 << endl; return os; } else if (n.numera == n.denom) { cout << 1 << endl; return os; } else { cout << n.numera << '/' << n.denom << endl; return os; }} istream& operator>>(istream &os, Fraction& n){ char slash = 0; return os >> n.numera >> slash >> n.denom;} 这篇关于error：overloaded'operator&lt;&lt;'必须是二进制运算符（有3个参数）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！