c++ - 错误 : More than one instance of overload function "findCircumference" matches the argument list

Question

我不知道该怎么办？我得到了与标题中一样的错误:错误:重载函数“findCircumference”的多个实例与参数列表匹配。

我正在为这项任务使用范围和功能。如果我能弄清楚这个错误，我就可以继续从事其他项目。请帮忙。

#include <iostream>
#include <iomanip>
using namespace std;


// This program will demonstrate the scope rules.

// PLACE YOUR NAME HERE


const double PI = 3.14;
const double RATE = 0.25;

void findArea(float, float);
void findCircumference(float, float);


int main()

{

    cout << fixed << showpoint << setprecision(2);
    float radius = 12;

    cout <<" Main function outer block" << endl;
    cout <<" LIST THE IDENTIFIERS THAT are active here" << endl << endl;
    {
        float area;
        cout << "Main function first inner block" << endl;  
        cout << "LIST THE IDENTIFIERS THAT are active here" << endl << endl;

        findArea(radius, area);// Fill in the code to call findArea here

        cout << "The radius = " << radius << endl;
        cout << "The area = " << area << endl << endl;
    }

    {
        float radius = 10;
        float circumference;

        cout << "Main function second inner block" << endl;
        cout << "LIST THE IDENTIFIERS THAT are active here" << endl << endl;

        findCircumference(radius, circumference);

        cout << "The radius = " << radius << endl;
        cout << "The circumference = " << circumference << endl << endl;

    }

    cout << "Main function after all the calls" << endl;
    cout << "LIST THE IDENTIFIERS THAT are active here" << endl << endl;

    return 0;
}

//  *********************************************************************
//                           findArea
//   
//   task:     This function finds the area of a circle given its radius
//   data in:  radius of a circle
//   data out: answer (which alters the corresponding actual parameter)
//
//   ********************************************************************


void findArea(float rad, float answer)
{

    cout << "AREA FUNCTION" << endl << endl;
    cout << "LIST THE IDENTIFIERS THAT are active here"<< endl << endl;
    answer = (rad*PI)*(rad*PI);
    cout << answer <<endl;
    // FILL in the code, given that parameter rad contains the radius, that
    // will find the areato be stored in answer

}

//  ******************************************************************************
//                           findCircumference
//   
//   task:     This function finds the circumference of a circle given its radius
//   data in:  radius of a circle
//   data out: distance (which alters the corresponding actual parameter)
//
//   *****************************************************************************



void findCircumference(float length, float& distance)

{
    cout << "CIRCUMFERENCE FUNCTION" << endl << endl;
    cout << "LIST THE IDENTIFIERS THAT are active here" << endl << endl; 
    distance = (length*2)*PI;
        cout << distance << endl;

    // FILL in the code, given that parameter length contains the radius, 
    // that will find the circumference to be stored in distance

}

Answer 1

您的前向声明是针对一个函数，该函数按值接受两个 float 参数

void findCircumference(float, float);

但是您的函数签名略有不同，一个 float 按值取值，第二个作为引用

void findCircumference(float, float&);
//                                 ^

您需要更改它们以匹配，大概是通过更正前向声明。