Question

所以我的错误是错误1错误LNK2019：未解析的外部符号＆＃34; class std :: basic_ostream＆gt; ＆安培; __cdecl运算符＆lt;＆lt;（class std :: basic_ostream＆gt;＆amp;，class Time const＆amp;）＆＃34;函数_main c：\ Users \ marklaptop \ documents \ visual studio 2013 \ Projects中引用了（?? 6 @ YAAAV？$ basic_ostream @ DU？$ char_traits @ D @ std @@@ std @@ AAV01 @ ABVTime @@@ Z） \ ConsoleApplication6 \ ConsoleApplication6 \ main.obj ConsoleApplication6

这令人困惑，因为在我学校的计算机实验室一切正常，我没有收到此错误。我保存了文本并在家中打开了，因为链接错误而无法正常工作

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

using namespace std;

int main()
{
    Time t1, t2, t3(123456), t4(-5);
    cout << "t1 = " << t1 << '\n';
    cout << "t2 = " << t2 << '\n';
    cout << "t3 = " << t3 << '\n';
    cout << "t4 = " << t4 << '\n';

    return 0;
}

现在是我的头文件 #ifndef TIME_H #define TIME_H

#include <iostream>

using namespace std;


class Time {

public:
// constructors
    Time();  //default constructor
    Time(int s); // conversion constructor
    Time(int d, int h, int m, int s); // days, hours, minutes,

    friend ostream& operator<<(ostream& out, const Time& t);

private:
    //member variables
    int day;
    int hour;
    int minute;
    int second;
};

#endif

最后是time.cpp文件

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

using namespace std;

Time::Time()
//default constructor. Initialize everything to start at 0
{
    day = 0;
    hour = 0;
    minute = 0;
    second = 0;
}
Time::Time(int s)
{
    if (s < 0)
    {
        day = hour = minute = second = 0;
    }
    else
    {
        second = s;
        day = second / 86400;
        hour = (second / 3600) % 24;
        minute = (second / 60) % 60;
        second = second % 60;
    }
}
Time::Time(int d, int h, int m, int s)
{
    day = d;
    hour = h;
    minute = m;
    second = s;
    if (h < 0){
        h = 0;
    }
    if (d < 0){
        d = 0;
    }
    if (m < 0){
        m = 0;
    }
    if (s < 0)  {
        s = 0;
    }


}

ostream& operator<<(ostream& out, const Time& t)
{
    out << t.day << "~";
    if (0 <= t.hour && t.hour <= 10)
    {
        out << "0" << t.hour << ":";
    }
    else
        out << t.hour << ":";

    if (0 <= t.minute && t.minute <= 10)
    {
        out << "0" << t.minute << ":";
    }
    else
        out << t.minute << ":";

    if (0 <= t.second && t.second <= 10)
    {
        out << "0" << t.second;
    }
    else
        out << t.minute;


    return out;

}

另外，最后一个问题是，任何人都可以帮助运营商的操作员超载＆gt;＆gt;，我可以使用比较和添加运算符等等，但我不明白如何使用提取运营商。我在努力朋友istream＆amp;运算符＆gt;＆gt;（istream＆amp; in，const Time＆amp; t）; 在头文件中，但无法弄清楚在cpp文件的函数体中写入什么。任何帮助都会很棒

好的，我的链接问题已经解决了，我理解了提取运算符的作用。我会把它放在标题中......

friend istream& operator>>(istream& in, const Time& t);

和time.cpp

 istream& operator>>(istream& in, const Time& t)
{
    in >> t.day;
    in >> t.hour;
    in >> t.minute;
    in >> t.second;


    return in;
}

main.cpp测试文件有这个

cout << "Enter first Time object (DAYS~HH:MM:SS):  ";
cin >> t1;

用户以（DAYS~HH：MM：SS）格式输入，所以只会说在＆gt;＆gt; t.day;接受将在（DAYS）的价值，是这么简单吗？

未解析的外部符号时间类

0 个答案: