C++ C++；将内容移动到不起作用的函数中

我正在做一个学校的项目，在这个项目中，我应该把不同的“FIXME”部分放到主函数之外的函数中。我以为我什么都做了，然后什么都没做。我重新开始，我把范围缩小到导致问题的功能。我将在下面的代码中标记它。这就是说，我可以很容易地将它格式化为函数，并且我的函数语法是正确的。但是，如果我在函数中有东西，答案是完全不同的，而不是没有。以下是没有函数的代码：

#include <iostream>
#include <iomanip>
#include <cmath>
#include <cstdlib>
#include <ctime>
using namespace std;

const double pi = 3.14159265;
const double grav = 9.8; // Earth gravity (m/s^2)

                     // Given time, angle, velocity, and gravity
                     // Update x and y values
void Trajectory(double t, double a, double v,
    double& x, double& y) {
    x = v * t * cos(a);
    y = v * t * sin(a) - 0.5 * grav * t * t;
    return;
}

// convert degree value to radians
double DegToRad(double deg) {
    return ((deg * pi) / 180.0);
}

// print time, x, and y values
void PrintUpdate(double t, double x, double y) {
    cout << "Time " << fixed << setprecision(0)
        << setw(3) << t << "   x = " << setw(3)
        << x << "   y = " << setw(3) << y << endl;
    return;
}

void PrintIntro() { //This function is going to print the intro to the game!
    cout << "Welcome to Upset Fowl!\n";
    cout << "The objective is to hit the Mean Swine by launching an Upset    Fowl.\n";
}

int main() {
    double t = 1.0; // time (s)
    double fowlY = 0.0; // object's height above ground (m)
    double fowlAngle = 0.0; // angle of launch of fowl (rad)
    double fowlVel = 0.0; // velocity of fowl (m/s)
    double fowlX = 0.0; // object's horiz. dist. from start (m)
    double fowlLandingX = 0.0; // fowl’s horiz. dist. from start (m)
    double swineX = 0.0; // distance to swine (m)
    double beforeSwineX = 0.0; // distance before swine that is acceptable as a hit (m)
    bool didHitSwine = false; // did hit the swine?

    srand(time(0));
    swineX = 50; //(rand() % 201) + 50; I took out the randomness so I can keep track of answers easily.

    PrintIntro();

    cout << "\nThe Mean Swine is " << swineX << " meters away.\n";
    cout << "Enter fowl launch angle (deg): ";
    cin >> fowlAngle;
    fowlAngle = ((fowlAngle * pi) / 180.0); // convert to radians
    cout << "Enter fowl launch velocity (m/s): ";
    cin >> fowlVel;


    // FIXME Make into a function called LaunchFaowl
    do {
        PrintUpdate(t, fowlX, fowlY);
        Trajectory(t, fowlAngle, fowlVel, fowlX, fowlY);
        t = t + 1.0;
    } while (fowlY > 0.0); // while above ground
    PrintUpdate(t, fowlX, fowlY);


    fowlLandingX = fowlX;


    // FIXME Make into a function called DtrmnIfHit
    beforeSwineX = swineX - 30;
    if ((fowlLandingX <= swineX) && (fowlLandingX >= beforeSwineX)) {
        cout << "Hit'em!!!" << endl;
        didHitSwine = true;
    }
    else {
        cout << "Missed'em..." << endl;
        didHitSwine = false;
    }

    return 0;
}

#include <iostream>
#include <iomanip>
#include <cmath>
#include <cstdlib>
#include <ctime>
using namespace std;

const double pi = 3.14159265;
const double grav = 9.8; // Earth gravity (m/s^2)

                         // Given time, angle, velocity, and gravity
                         // Update x and y values
void Trajectory(double t, double a, double v,
    double& x, double& y) {
    x = v * t * cos(a);
    y = v * t * sin(a) - 0.5 * grav * t * t;
    return;
}

// convert degree value to radians
double DegToRad(double deg) {
    return ((deg * pi) / 180.0);
}

// print time, x, and y values
void PrintUpdate(double t, double x, double y) {
    cout << "Time " << fixed << setprecision(0)
        << setw(3) << t << "   x = " << setw(3)
        << x << "   y = " << setw(3) << y << endl;
    return;
}

void PrintIntro() { //This function is going to print the intro to the game!
    cout << "Welcome to Upset Fowl!\n";
    cout << "The objective is to hit the Mean Swine by launching an Upset Fowl.\n";
}

void GetUsrInpt(double piggy, double slope, double Velocity) { // FIXME Make into a function called GetUsrInpt
    cout << "\nThe Mean Swine is " << piggy << " meters away.\n";
    cout << "Enter fowl launch angle (deg): ";
    cin >> slope;
    slope = ((slope * pi) / 180.0); // convert to radians
    cout << "Enter fowl launch velocity (m/s): ";
    cin >> Velocity;
}

int main() {
    double t = 1.0; // time (s)
    double fowlY = 0.0; // object's height above ground (m)
    double fowlAngle = 0.0; // angle of launch of fowl (rad)
    double fowlVel = 0.0; // velocity of fowl (m/s)
    double fowlX = 0.0; // object's horiz. dist. from start (m)
    double fowlLandingX = 0.0; // fowl’s horiz. dist. from start (m)
    double swineX = 0.0; // distance to swine (m)
    double beforeSwineX = 0.0; // distance before swine that is acceptable as a hit (m)
    bool didHitSwine = false; // did hit the swine?

    srand(time(0));
    swineX = 50; //(rand() % 201) + 50;

    PrintIntro();

    GetUsrInpt(swineX, fowlAngle, fowlVel);


    // FIXME Make into a function called LaunchFaowl
    do {
        PrintUpdate(t, fowlX, fowlY);
        Trajectory(t, fowlAngle, fowlVel, fowlX, fowlY);
        t = t + 1.0;
    } while (fowlY > 0.0); // while above ground
    PrintUpdate(t, fowlX, fowlY);


    fowlLandingX = fowlX;


    // FIXME Make into a function called DtrmnIfHit
    beforeSwineX = swineX - 30;
    if ((fowlLandingX <= swineX) && (fowlLandingX >= beforeSwineX)) {
        cout << "Hit'em!!!" << endl;
        didHitSwine = true;
    }
    else {
        cout << "Missed'em..." << endl;
        didHitSwine = false;
    }

    return 0;
}

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使用名称空间std；
常数双pi=3.14159265；
常量双重力=9.8；//地球重力（m/s^2）
//给定时间、角度、速度和重力
//更新x和y值
空位轨迹（双t、双a、双v、，
双倍（x、y和y）{
x=v*t*cos（a）；
y=v*t*sin（a）-0.5*grav*t*t；
返回；
}
//将度值转换为弧度
双除雾器（双度）{
返回（（deg*pi）/180.0）；
}
//打印时间、x和y值
无效打印更新（双t、双x、双y）{
cout斜率必须通过参考传递：

void GetUsrInpt(double piggy, double& slope, double Velocity) { // FIXME    Make into a function called GetUsrInpt
   cout << "\nThe Mean Swine is " << piggy << " meters away.\n";
   cout << "Enter fowl launch angle (deg): ";
   cin >> slope;
   slope = ((slope * pi) / 180.0); // convert to radians
   cout << "Enter fowl launch velocity (m/s): ";
   cin >> Velocity;
 }

以相同的方式处理在函数中更改其值的其他变量，您将完成此操作。
斜率必须通过引用传递：

void GetUsrInpt(double piggy, double& slope, double Velocity) { // FIXME    Make into a function called GetUsrInpt
   cout << "\nThe Mean Swine is " << piggy << " meters away.\n";
   cout << "Enter fowl launch angle (deg): ";
   cin >> slope;
   slope = ((slope * pi) / 180.0); // convert to radians
   cout << "Enter fowl launch velocity (m/s): ";
   cin >> Velocity;
 }

以相同的方式处理其他变量，您可以在函数中更改它们的值，这样您就可以完成它

您已经设置了函数GetUsrInpt，将双参数传递为>“按值传递”因此，只有swineX、>fowlAngle和fowlVel的值的副本被传递给函数。在>函数中更改它们不会更改它们在主函数中的值。如果要>更改它们并让主函数知道，则必须使用指向变量的指针通过>引用传递。
像这样

//按如下方式调用函数：

GetUsrInpt( &swineX, &fowlAngle, &fowlVel );

您已经设置了函数GetUsrInpt，将双参数传递为>“按值传递”因此，只有swineX、>fowlAngle和fowlVel的值的副本被传递给函数。在>函数中更改它们不会更改它们在主函数中的值。如果要>更改它们并让主函数知道，则必须使用指向变量的指针通过>引用传递。
像这样

//按如下方式调用函数：

GetUsrInpt( &swineX, &fowlAngle, &fowlVel );

请发布请发布非常感谢，这很有效。我想我现在明白了如何构建它们。再次感谢！非常感谢，这很有效。我想我现在明白了如何构建它们。再次感谢！