小编Kyl*_*yle的帖子

刚进入C++,我有一个简单的问题.

编译完成后

g++ *.cpp -o output

我收到此错误:

error: 'ostream' in 'class Dollar' does not name a type

这些是我的三个文件:

main.cpp中

#include <iostream>
#include "Currency.h"
#include "Dollar.h"

using namespace std;

int main(void) {
    Currency *cp = new Dollar;

    // I want this to print "printed in Dollar in overloaded << operator"
    cout << cp;
    return 0;
}

Dollar.cpp

#include <iostream>
#include "Dollar.h"

using namespace std;

void Dollar::show() {
    cout << "printed in Dollar";
}

ostream & operator << (ostream &out, const Dollar …