我正在尝试编写一个程序
•使用参数化构造函数,使用随机类提供的随机数,定义五个圆形对象的数组,其中半径设置
•使用setRadius方法使用随机类提供的随机数来定义五个圆形对象的第二个数组,其中半径设置为
•使用 getArea()
显示每个阵列中每个圆的区域
我需要帮助使用getArea()方法显示每个数组中每个圆的区域的问题,我需要访问每个数组中半径值为五个圆的数组,然后计算出区域3.14 半径半径 . 然后将区域显示在屏幕上 .
在做了一些研究之后,我是否需要实例化我在 Circle myCircle;
中输入的Circle对象 . 然而它出现了错误说法
1> main.obj:错误LNK2019:函数_main中引用的未解析的外部符号“public:__thiscall Circle :: Circle(void)”(?? 0Circle @@ QAE @ XZ)
Circle.h文件
#pragma once
#include <string>
class Circle
{
private:
float Radius;
public:
Circle(); // initialised radius to 0
Circle(float r); // accepts an argument and assign its value to the radius attribute
void setRadius(float r); // sets radius to a value provided by its radius parameter (r)
float getRadius(); // returns the radius of a circle
float getArea(); // calculates and returns the areas of its circle
};
Random.h文件
#pragma once
#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
class Random
{
public:
static void initialiseSeed();
// random number initialised
// random number has been initialised to the current time.
static int random(int lower, int upper);
// this function will return a positive random number within a specific lower and
// upper boundary.
};
Main.cpp文件
#include <iostream>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <iomanip>
using namespace std;
// Include header files
#include "Circle.h"
#include "Random.h"
int main()
{
// Instantiate myCircle object
//Circle myCircle;
// Array 1
// an array of five circles objects where radius is set using the random number
// provided by the random class utilising the parameterised constructor
int CircleArrayOne [5]; // store the numbers
const int NUM = 5; // Display 5 random numbers
srand(time(NULL)); // seed the generator
// populate the array by calling the random function from the random class
// within the lower and upper bounds
for(int x = 0; x < NUM; ++x)
{
CircleArrayOne[x] = Random::random(1, 40); // assumed 0 and 40 as the bounds
}
// Below is the code I use to output the array to the screen to make sure
// that is output the correct number of values and it generate number between 1 and 40
// I am doing this to test the code above that populate the array within lower and upper
// bounds
cout << "Checking the radius in the Array 1." << endl;
for(int i = 0; i < NUM; ++i)
{
cout << CircleArrayOne[i] << endl;
}
// Array 2
// a second array of five circles objects where radius is set using the random number
// provided by the random class utilising the setRadius method
float CircleArrayTwo [5]; // store the numbers
const int Number = 5; // Display 5 random numbers
srand(time(NULL)); // seed the generator
// populate the array with random numbers
for(int i = 0; i < Number; ++i)
{
CircleArrayTwo[i] = rand()%100;
}
// Below is the code I use to output the array to the screen to make sure
// that is output the correct number of values and it generate random values
cout << "Checking the radius in the Array 2." << endl;
for(int i = 0; i < Number; ++i)
{
cout << CircleArrayTwo[i] << endl;
}
// Display the area of each Circle within each array using getArea()
cout << "\nThe area of each circle within array 1: " << endl;
cout << "\nThe area of each circle within array 2: " << endl;
// Display a message that indicates which set of circle has the largest
// combined area
cout << "\nArray: " << "had the largest combined area." << endl;
// Display a message that indicates which set contains the circle
// with the largest area
cout << "\nArray: " << "contain the circle with the largest area.\n" << endl;
system("PAUSE");
return 0;
}
// Calling Circle(float r) from Circle Class
Circle::Circle(float r)
{
if (r<=0)
{
cout << "An invalid radius has been detected." << endl;
cout << "The radius has been set to 1.0" << endl;
Radius = 1.0;
}
else
Radius = r;
}
// Calling getArea() from Circle Class
float Circle::getArea()
{
// Area = pi * radius * radius
return 3.14 * Radius * Radius;
}
// Calling setRadius(float r) from Circle Class
void Circle::setRadius(float r)
{
rand()%100;
Radius = r;
}
// Calling getRadius() from Circle Class
float Circle::getRadius()
{
return Radius;
}
// Calling random(int lower, int upper) from Random Class
int Random::random(int lower, int upper)
{
int range = upper - lower + 1;
return (rand() % range + lower);
}
// Calling initialiseSeed() from Random Class
void Random::initialiseSeed()
{
srand((unsigned int)time(0));
rand()%100;
}
如何使用 getArea()
函数获取每个数组中每个圆的面积
3 回答
您还没有为
Circle
的默认构造函数添加定义到main.cpp .
您需要定义
Circle
的默认构造函数:这也将
Radius
初始化为0.0F
您没有给出
Circle()
默认构造函数的定义(实现),但仅针对Circle(float)
构造函数 . 一种可能性是:另请注意,当您在头文件中省略
Circle();
时,您不会遇到此错误(因为这会阻止编译器为您添加默认构造函数) .