重载提取和插入操作符pt2 C++

Question

这是我之前发布的问题的pt2，如果它在我编辑后是否会被回答，我想，因为它已经被认为是“回答”了。

好的，现在我正在尝试输出a+ bi：

std::ostream& operator<< (std::ostream& out, complex const& c) {
    return out << c.getReal() << "+" << c.getImag() << "i";
}

并供投入：

std::istream& operator>> (std::istream& in, complex& c) {
    double h, j;
    if (in >> h >> "+" >> j >> "i") {
        c.set(h, j);
    }
    return in;
}

但是，在编译时会出现以下错误：

这是针对我的complex.cpp文件(类复杂实现文件)的第181行，其中if (in >> h >> "+" >> j >> "i") {位于上述函数定义的位置：

binary '>>': no operator found which takes a right-hand operand of type 'const char [2]' (or there is no acceptable conversion) 

下面是friend std::istream &operator>> (std::istream &in, complex& c);原型所在的comp.h文件的第45行(每个错误都是单独的，共7行)的所有内容。

'istream':is not a member of 'std'

syntax error missing ';' before '&'

'istream':'friend' not permitted on data declarations

missing type specifier-int assumed. Note:C++ does not support default-int

unexpected token(s) preceding';'


namespace "std" has no member "istream"

namespace "std" has no member "istream"

下面是我的comp.h文件的第46行，其中

friend std::ostream &operator<<(std::ostream &out, complex c);

找出

'ostream': is not a member of 'std'

syntax error: missing ';' before '&'

'ostream':'friend' not permitted on data declarations

missing type specifier -int assumed.Note: C++ does not support default-int

unexpected token(s) preceding ';'

namespace "std" has no member "ostream"

namespace "std" has no member "ostream"

我注意到两者都是相同类型的错误。注:我有

#include<iostream>

using namespace std;

complex.cpp文件和main.cpp文件

Answer 1

您正在尝试在只读字符串中输入

if (in >> h >> "+" >> j >> "i")

这是行不通的。您需要做的是创建一个变量来存储输入的文本内容。因为不需要内容，所以我们可以在做完后把它扔掉。这会给你一些线索

std::istream& operator>> (std::istream& in, complex& c) {
    double h, j;
    char eater;
    if (in >> h >> eater >> j >> eater) { // eater now consumes the + and i
        c.set(h, j);
    }
    return in;
}

至于头文件中的错误，您需要在头文件中包含#include <iostream>，以便编译器知道istream和ostream是什么。