涉及函数& if / else if语句 [英] Class involving functions & if/else if statements
问题描述
该任务是编写一个程序，允许用户计算各种形状的面积和体积。不允许对 PI 使用任何全局变量。
The assignment is to write a program that will allow the user to calculate the area and volume of various shapes. Not allowed to use any global variables with the one exception for PI.
#include <iostream>
#include <iomanip>
using namespace std;
//Functions
void showMenu(int &);
double area (double, double);
double area (double);
double volume (double, double, double);
double volume (double);
int main()
{
int choice;
double area, volume;
const double PI = 3.14;
do
{
showMenu();
cin >> choice;
if (choice < 1 || choice > 5 )
{
cout << "Please select a valid choice of 1-5: " << endl;
cin >> choice;
}
else if (choice == 1)
{
area = double area (double length, double width);
cout << "The area of the rectangle is: " << endl;
}
else if (choice == 2)
{
area = double area (double radius);
cout << "The area of the circle is: " << endl;
}
else if (choice == 3)
{
volume = double volume (double length, double width, double height);
cout << "The volume for a box is: " << endl;
}
else if (choice == 4)
{
volume = double volume (double radius);
cout << "The volume of a sphere is: " << endl;
}
}
while (choice != 5);
return 0;
}
void ShowMenu(int &choice)
{
cout << "1. Calculate the area of a rectangle";
cout << "2. Calculate the area of a circle";
cout << "3. Calculate the volume for a box";
cout << "4. Calculate the volume of a sphere";
cout << "5. Quit";
}
double area (double length, double width);
{
cout << "Enter the length: ";
cin >> length;
cout << "Enter the width: ";
cin >> width;
area = lenght * width;
}
double area (double radius);
{
cout << "Enter the radius: ";
cin >> radius;
area = PI * (radius * 2);
}
double volume (double length, double width, double height);
{
cout << "Enter the length: ";
cin >> length;
cout << "Enter the width: ";
cin >> width;
cout << "Enter the height: ";
cin >> height;
volume = length * width * height;
}
double volume (double radius);
{
cout << "Enter the radius: ";
cin >> radius;
volume = (4/3) * PI * (radius * 3)
}
我得到的错误：
1> c：\users\dylan\documents\visual studio 2010 \projects\lab4\lab4\labfour.cpp（20）：错误C2660：'showMenu'：函数不接受0个参数
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp(20): error C2660: 'showMenu' : function does not take 0 arguments
1> c： \users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp（31）：错误C2062：输入double意外
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp(31): error C2062: type 'double' unexpected
1> c：\users\dylan\documents\visual studio 2010 \projects\lab4\lab4\labfour.cpp（38）：错误C2062：类型'double'意外
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp(38): error C2062: type 'double' unexpected
1> c：\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp（45）：错误C2062：输入double意外
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp(45): error C2062: type 'double' unexpected
1> c：\users\dylan\documents\visual studio 2010\projects\lab4\lab4 \labfour.cpp（52）：error C2062：type'double'unexpected
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp(52): error C2062: type 'double' unexpected
1> c：\users\dylan\documents\visual studio 2010 \projects\lab4\lab4\labfour.cpp（71）：错误C2447：'{'：缺少函数头（旧式正式列表？）
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp(71): error C2447: '{' : missing function header (old-style formal list?)
1> c：\users\dylan\documents\visual studio 2010 \projects\lab4\lab4\labfour.cpp（80）：错误C2447：'{'：缺少函数头（old-样式正式列表？）
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp(80): error C2447: '{' : missing function header (old-style formal list?)
1> c：\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour .cpp（87）：error C2447：'{'：missing function header（old-style formal list？）
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp(87): error C2447: '{' : missing function header (old-style formal list?)
1> c：\users\dylan\\ \\ documents \visual studio 2010 \projects\lab4\lab4\labfour.cpp（98）：错误C2447：'{'：缺少函数头（旧式正式列表？）
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\labfour.cpp(98): error C2447: '{' : missing function header (old-style formal list?)
1> Lab4.cpp
1> c：\users\dylan\documents\visual studio 2010\projects\lab4\lab4\lab4.cpp 117）：warning C4244：'='：从'double'转换为'float'，可能会丢失数据
1> Lab4.cpp 1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\lab4.cpp(117): warning C4244: '=' : conversion from 'double' to 'float', possible loss of data
1> c：\users\dylan\\ \\ documents \visual studio 2010 \projects\lab4\lab4\lab4.cpp（127）：错误C2447：'{'：缺少函数头（旧式正式列表？）
1>c:\users\dylan\documents\visual studio 2010\projects\lab4\lab4\lab4.cpp(127): error C2447: '{' : missing function header (old-style formal list?)
推荐答案
更正编译时错误不是一项艰巨的任务。按照错误消息，尝试找出问题。我会给你一些例子在你的代码来解决错误。您的代码有许多错误，显示您需要在C ++中练习更多。
Correcting compile time errors is not a hard task. Follow error messages and try to find out the problem. I will show you some examples in your code to solve errors. Your code has many error which shows you need practice more in C++.
showMenu 的声明是 void showMenu（int&）但是你是通过 showMenu（）：
$ b
The declaration of showMenu is void showMenu(int &) but you are calling it by showMenu():
void showMenu(int &);
^^^^^
Remove it
您不应传递类型：
area = double area (double length, double width);
^^^^^^ ^^^^^^ ^^^^^^
更多，当实现一个函数时，你不应该在函数签名之后放置; ：
More, when implementing a function, you shall not put ; after function signature:
double area (double radius); <--- remove semicolon
{
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