如何将返回值传递给另一个 function 并将返回值分配给该 function 内的变量？

Question

我的程序由 3 个文件组成。 clockType.h - class function 原型，clockTypeImp.cpp - 函数定义，以及测试程序 testClockClass.cpp。

我试图在下面的代码中将第一个 function 的返回值传递给下一个 function。 我想我应该将它作为参考周界或指针*传递。

您可以看到我将返回值分配给变量diffSec的失败尝试。

（我想要做的是将两个时钟之间的秒差转换为HH:MM:SS ）。

我的clockTypeImp.cpp 实现文件的一部分：

int clockType::clockDiffseconds(clockType otherClock) {
    int elapsedSec;
    return (abs(elapsedTimeSeconds() - otherClock.elapsedTimeSeconds()));
}

void clockType::secondsToHHMMSS() {
    int diffSec = clockType::clockDiffseconds(clockType otherClock);
    int diffHours = diffSec/3600;
    int diffMinutes = (diffSec/60)%60;
    int diffSeconds = diffSec%60;
    cout << "Converted to HH:MM:SS: " << diffHours << ":" << diffMinutes << ":" << diffSeconds;
}

我的clockType.h文件的一部分，clockType来自：

class clockType {
     public:
     void remainingTimeSeconds(int& totalEndSec);     // Function to convert clock to time remaining in seconds.
     int clockDiffseconds(clockType otherClock); // Function for finding difference in time between clocks.
     void secondsToHHMMSS();    // Function for converting seconds to HH:MM:SS.
     bool equalTime(const clockType& otherClock) const;     // Function to compair the two times.
     private:
     int hr;     // Variable to store the hours.
     int min;    // Variable to store the minutes.
     int sec;    // Variable to store the seconds.
};

这是我的测试程序的一部分。

#include <iostream>
#include <iomanip>
#include "clockType.h"

using namespace std;

int main() {
        clockType myClock;
        clockType yourClock;

        int hours;
        int minutes;
        int seconds;
        int elapsedSec;
        int totalEndSec;

        cout << endl << "myClock Time is not set:\n";
        myClock.printTime();

        cout << endl << "myClock Time is set:\n";
        myClock.setTime(9, 3, 30);
        myClock.printTime();
        cout << endl;

        cout << endl << "yourClock Time is not set:\n";
        yourClock.printTime();

        cout << endl << "yourClock Time is set:\n";
        yourClock.setTime(5, 45, 16);
        yourClock.printTime();
        cout << endl << endl;

        if (myClock.equalTime(yourClock)) {
                cout << "Both times are equal." << endl;
        } else {
                cout << "The two times are not equal." << endl;
        }

        cout << endl << "Set the time for myClock\nEnter the hours, minutes, and seconds:\n";

     yourClock.remainingTimeSeconds(totalEndSec);
     cout << "\x1B[32m-->\033[0m" << " The total remaining seconds of \x1B[32myourClock\033[0m is: " << totalEndSec << endl;

     myClock.remainingTimeSeconds(totalEndSec);
     cout << "\x1B[33m-->\033[0m" << " The total remaining seconds of \x1B[33mmyClock\033[0m is: " << totalEndSec << endl;
        
     cout << endl;
        
     cout << "\x1B[34m-->\033[0m" << " The difference in seconds between the \x1B[34mtwo clocks\033[0m is: " << myClock.clockDiffseconds(yourClock) << endl;

如果您需要查看文件的完整代码，请告诉我。

Answer 1

clockDiffseconds()是一种非static方法，它作用this ，计算this时钟与另一个时钟otherClock之间的秒差。 那也行。

但是secondsToHHMMSS()没有otherClock的概念。 它也是一个仅作用this的非static方法。 因此， secondsToHHMMSS()有意义，您有几个选择：

• 重新思考secondsToHHMMSS()对您的实际意义。 按照您编写的方式，它应该按原样打印this秒数。 在这种情况下，使用clockDiffseconds()返回的值构造一个新的clockType object，其elapsedTimeSeconds()仅返回该值，然后在该新clockType object 上调用secondsToHHMMSS() ，例如：

   class clockType { public:... clockType clockDiff(clockType otherClock) const; void secondsToHHMMSS() const;... };

   clockType clockType::clockDiff(clockType otherClock) const { int elaspedSec = abs(elapsedTimeSeconds() - otherClock.elapsedTimeSeconds()); return clockType(elaspedSec); // add a constructor to clockType that stores elaspedSec in such // a way that its elapsedTimeSeconds() can then return it... } void clockType::secondsToHHMMSS() const { int elapsedSec = elapsedTimeSeconds(); int hours = elapsedSec/3600; int minutes = (elapsedSec/60)%60; int seconds = elapsedSec%60; cout << "Converted to HH:MM:SS: " << hours << ":" << minutes << ":" << seconds; }

   clockType myClock, yourClock, elapsed;... elapsed = myClock.clockDiff(yourClock); elapsed.secondsToHHMMSS();...

• 否则，如果您真的希望secondsToHHMMSS()以秒为单位表示两个时钟之间的差异，那么您必须将otherClock作为参数传递给secondsToHHMMSS() ，就像您已经对clockDiffseconds()所做的那样，例如：

   class clockType { public:... int clockDiffseconds(clockType otherClock) const; void secondsToHHMMSS(clockType otherClock) const;... };

   int clockType::clockDiffseconds(clockType otherClock) const { return abs(elapsedTimeSeconds() - otherClock.elapsedTimeSeconds()); } void clockType::secondsToHHMMSS(clockType otherClock) const { int diffSec = clockDiffseconds(otherClock); int diffHours = diffSec/3600; int diffMinutes = (diffSec/60)%60; int diffSeconds = diffSec%60; cout << "Converted to HH:MM:SS: " << diffHours << ":" << diffMinutes << ":" << diffSeconds; }

   clockType myClock, yourClock;... myClock.secondsToHHMMSS(yourClock);...

• 否则，请考虑将secondsToHHMMSS()更改为static方法，然后将所需的秒数作为参数传递，例如从早期调用clockDiffseconds() ，例如：

   class clockType { public:... static void secondsToHHMMSS(int seconds);... };

   void clockType::secondsToHHMMSS(int seconds) const { int hours = seconds/3600; int minutes = (seconds/60)%60; seconds = seconds%60; cout << "Converted to HH:MM:SS: " << hours << ":" << minutes << ":" << seconds; }

   clockType myClock, yourClock;... int diffSec = myClock.clockDiffseconds(yourClock); clockType::secondsToHHMMSS(diffSec);...