調用的C ++編譯器錯誤

Question

在我的計算機科學課上，我們正在制作一個程序，要求對4個等腰梯形的高度，底部和頂部進行測量，計算周長並確定哪個周長最大。 我的程序還沒有完成，但是我收到錯誤消息，說沒有匹配函數可以調用askInput ， calcPerimeter和findMax 。 這是上下文代碼（很抱歉，如果答案很明顯，或者我的代碼草率，這是我參加的第一個編程類）。

#include <iostream>
#include <string>

using namespace std;

void intro();
void askInput();
double calcPerimeter();
double findMax();
double highest;

int main()
{
    intro();

    double t1, b1, h1, p1;  //Top, bottom, height, and perimiter of first trapezoid
    double t2, b2, h2, p2,
           t3, b3, h3, p3,
           t4, b4, h4, p4;  //other four trapezoids
    double max;             //largest perimeter

    askInput(t1, b1, h1, "first");
    askInput(t2, b2, h2, "second");
    askInput(t3, b3, h3, "third");
    askInput(t4, b4, h4, "fourth");

    p1 = calcPerimeter(t1, b1, h1);
    p2 = calcPerimeter(t2, b2, h2);
    p3 = calcPerimeter(t3, b3, h3);
    p4 = calcPerimeter(t4, b4, h4);

    max = findMax(p1, p2, p3, p4);

    cout << "Results" << endl;
    cout << "\tFirst: \tTop:" << t1 << "\tBottom: " << b1 << "\tHeight: " << h1 << "\tPerimeter: " << p1 << endl;
    cout << "\tSecond: \tTop:" << t2 << "\tBottom: " << b2 << "\tHeight: " << h2 << "\tPerimeter: " << p2 << endl;
    cout << "\tThird: \tTop:" << t3 << "\tBottom: " << b3 << "\tHeight: " << h3 << "\tPerimeter: " << p3 << endl;
    cout << "\tFourth: \tTop:" << t4 << "\tBottom: " << b4 << "\tHeight: " << h4 << "\tPerimeter: " << p4 << endl;
    cout << endl << "\tLargest Perimeter: " << highest << endl;


    system("pause");
    return 0;
}

void intro()
{
    cout << "Lab G: Trapezoid with largest perimeter" << endl;
    cout << "---------------------------------------" << endl; \
    cout << "This program will calculate the perimeter of four trapezoids." << endl;
    cout << "You will have to enter the top, bottom, and height of each trapezoid." << endl;
    cout << "The program will then find the trapezoid with the largest perimeter and output it." << endl;
}

void askInput(double &top, double &bottom, double &height, string whichT)
{
    cout << "Enter values for the " << whichT << " trapezoid." << endl;
    cout << "\tTop: ";
    cin >> top;
    cout << "\tBottom: ";
    cin >> bottom;
    cout << "\tHeight: ";
    cin >> height;
}

double calcPerimeter(double top, double bottom, double height)
{
    double answer;

    //some calculations

    return answer;
}

double findMax(double a, double b, double c, double d)
{
    double highest;
    highest = a;
    if (b > highest)
    {
        highest = b;
    }
    if (c > highest)
    {
        highest = c;
    }
    if (d > highest)
    {
        highest = d;
    }
    return highest;
}

Answer 1

聲明中的函數簽名必須與實現中的簽名匹配。 這意味着聲明必須包含所有需要的函數參數類型。

void askInput(double &top, double &bottom, double &height, string whichT);

double calcPerimeter(double top, double bottom, double height);

double findMax(double a, double b, double c, double d);

Answer 2

這些函數的原型不包含參數。 askInput()與askInput(double &, double&, double&, string)是一個不同的函數。

Answer 3

自從我從事C ++以來已經有一段時間了，但是我認為我至少看到了兩個問題-

1. 您需要在函數頂部聲明其完整簽名。
2. 至少對於askInput您要傳入值並取消引用它們。 這在我看來很奇怪。

希望這可以幫助！

Answer 4

您的聲明和函數定義不匹配。 像定義中一樣聲明它們，這應該起作用。

 void askInput(); --> 
 void askInput(double &, double &, double &, string );

 double calcPerimeter();-->
 double calcPerimeter(double & , double & , double& );

 double findMax();-->
 double findMax(double &, double &, double &, double &);