13函数C++计算器，采用2-3个参数
13函数C++计算器，采用2-3个参数
提问于 2017-02-25 17:26:51
我决定编写一个(或多或少简单的) C++计算器；init.cpp通常获取大部分用户输入，并调用这些函数。这是我的档案：
//init.cpp (main file)
#include "includes.hpp"
int main()
{
char t = '\t'; //tab character, used for menu formatting
char nl = '\n'; //new line character, used for menu formatting
char esc = '\0'; //null character, not used yet
float a,b,c; //these are the arguments passed to the functions
int in; //this is the user-input that determines what function is called
cout<<"enter three values:\n";
cin>>a>>b>>c; //gets the function arguments
displayMenu(t,nl,esc);//displays a simple number: tabs function name
cout<<"enter the item number for the function you want to call:\n";
cin>>in;
//the following switch/case calls the appropriate function
switch(in)
{
case 0:
add(a,b,c);
break;
case 1:
subtract(a,b,c);
break;
case 2:
multiply(a,b,c);
break;
case 3:
divide(a,b,c);
break;
case 4:
square(a,b,c);
break;
case 5:
raise(a,b,c);
break;
case 6:
log(a,b,c);
break;
case 7:
Sin(a,b,c);
break;
case 8:
square_root(a,b,c);
break;
case 9:
Tan(a,b,c);
break;
case 10:
Acos(a,b,c);
break;
case 11:
Ceil(a,b,c);
break;
case 12:
Floor(a,b,c);
break;
default:
cerr<<"error. unkown input\n";
}
}这是我的"includes.hpp"：
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include "Headers/displayMenu.hpp"
#include "Headers/add.hpp"
#include "Headers/subtract.hpp"
#include "Headers/multiply.hpp"
#include "Headers/divide.hpp"
#include "Headers/square.hpp"
#include "Headers/raise.hpp"
#include "Headers/log.hpp"
#include "Headers/Sin.hpp"
#include "Headers/square_root.hpp"
#include "Headers/Tan.hpp"
#include "Headers/Acos.hpp"
#include "Headers/Ceil.hpp"
#include "Headers/Cloor.hpp"
using namespace std;add.hpp：
void add(float a, float b, float c)
{
float result = a + b + c;
std::cout<<result<<"\n";
}Acos.hpp：
void Acos(float a, float b, float c)
{
std::cout<<acos(a)<<"\n";
std::cout<<acos(b)<<"\n";
std::cout<<acos(c)<<"\n";
}Tan.hpp：
void Tan(float a, float b, float c)
{
std::cout<<tan(a)<<"\n";
std::cout<<tan(b)<<"\n";
std::cout<<tan(c)<<"\n";
}subtract.hpp：
void subtract(float a, float b, float c)
{
float result_1 = a - b;
float result_2 = b - a;
float result_3 = )(result_1 + result_2) / 2);
std::cout<<result_3<<"\n";
}square_root.hpp：
void square_root(float a, float b, float c)
{
if( a < 0.0 || b < o.o || c > 0.0)
{
std::cerr<<"error. in function square_root(), attempted to take square root of a negative int\n";
exit(1);
}else{
std::cout<<sqrt(a)<<"\n";
std::cout<<sqrt(b)<<"\n";
std::cout<<sqrt(c)<<"\n";
}
}square.hpp：
void square(float a, float b, float c)
{
float result_1 = a * a;
float result_2 = b * b;
float result_3 = c * c;
std::cout<<result_1<<"\n";
std::cout<<result_2<<"\n";
std::cout<<result_3<<"\n";
}Sin.hpp：
void Sin(float a, float b, float c)
{
std::cout<<sin(a)<<"\n";
std::cout<<sin(b)<<"\n";
std::cout<<sin(c)<<"\n";
}raise.hpp：
void raise(float a, float b, float c)
{
const int aSize = 3;
float AR[aSize]; //stores a results
float BR[aSize]; //stores b results
float CR[aSize]; //stores c resutls
float PW[aSize]; //stores the powers for the pow() function
int count;
for(count = 0; count < aSize; count++)
{
std::cout<<"value:\n";
std::cin>>PW[count]; //gets the powers for the function and stores them in the array
}
for(count = 0; count < aSize; count++)
{
AR[count] = pow(a, PW[count]);
BR[count] = pow(b, PW[count]);
CR[count] = pow(c, PW[count]);
}
for( count = 0; count < aSize; count++)
{ //the code for this for block doesn't look like this on my local machine, I just implemented the following code while posting this
std::cout<<a<<" raised to the: "<<PW[count]<<" power is: "<<AR[count];
std::cout<<b<<" raised to the: "<<PW[count[<<" power is: "<<BR[count];
std::cout<<c<<" raised to the: "<<PW[count]<<" power is: "<<CR[count];
}
}multiply.hpp：
void multiply(float a, float b, float c)
{
float result_1 = a * b * c;
std::cout<<result_1<<"\n";
}log.hpp：
void log(float a, float b, float c)
{
std::cout<<log(a)<<"\n";
std::cout<<log(b)<<"\n";
std::cout<<log(c)<<"\n";
}Floor.hpp：
void Floor(float a, float b, float c)
{
std::cout<<floor(a)<<"\n";
std::cout<<floor(b)<<"\n";
std::cout<<floor(c)<<"\n";
}divide.hpp：
void divide(float a, float b, float c)
{
if( a == 0 || b == 0 || c == )
{ //I wanted to put this in a fucntion called checkVal(), but I had problems including it
std::cerr<<"error. in function divide(), division by zero attempted\n";
exit(1);
}else{
float result_1 = a / b;
float result_2 = b / a;
float result_3 = ((result_1 + result_2) / 2);
std::cout<<result_3<<"\n";
}
}displayMenu.hpp：
void displayMenu(char t, char nl, char esc)
{
const int aSize = 13;
string menu_name[] = {"add","subtract","multiply","divide","square","raise","log","sin","square_root","tan","acos","ceil","floor"};
int menu_number[] = {0,1,2,3,4,5,6,7,8,9,10,11,12};
int counter;
std::cout<<"item number"<<t<<"function\n";
for(counter = 0; counter < aSize; counter++)
{
std::cout<<menu_number[counter]<<":"<<t<<t<<menu_name[counter]<<nl;
}
}Ceil.hpp：
float Ceil(float a, float b, float c)
{
std::cout<<ceil(a)<<"\n";
std::cout<<ceil(b)<<"\n";
std::cout<<ceil(c)<<"\n";
}最后，这里是我的makefile：
CPPFLAGS = -lm -o
init: init.cpp
g++ ini.cpp $(CPPFLAGS) init.exe
.PHONY: clean
clean:
rm *.exe这是所有的15个文件项目。如果您想复制和粘贴代码以查看它是否运行，请随意使用。但就目前而言，我是否可以作出任何改善？还是有一只虫子等着被发现？
回答 3
Code Review用户
发布于 2017-02-26 02:27:00
您应该查找命令模式。
此外，长开关也可以被地图所取代。
using Action = std::function<void(float, float, float)>;
using ActionMap = std::map<int, Action>;
ActionMap actionMap = {{0, add}, {1, subtract}, ...};
... Code.
actionMap[in](a,b,c); // Calls the appropriate functionCode Review用户
发布于 2017-02-25 21:14:25
我看到了一些逻辑错误，使我相信这不会编译。以下是一些简短的评论：
- 使用标准名称空间:您可能需要在使用其中项的每一点上指示具有范围分辨率的标准命名空间，或者预先使用Using关键字。
- 神奇数字:我可以看到，用户输入时使用数字条目，但一般来说，最好在代码中使用定义的值，以便于阅读和使用。
代码似乎是从其他地方粘贴的，您缺少一些操作数/操作符，可能需要首先手动修复这些操作数/运算符。
Code Review用户
发布于 2017-02-28 16:15:20
我看到了一些问题，但我将重点讨论代码中缺少的一些内容：
在"square_rood.hpp“中，在if中检查数字是否小于0，您已经在b == 0.0中嵌入了b < o.o。你在检查"c“是否大于0，而不是它是否更小。
在devide.hpp中的if中，要检查一个数字是否为零，您只有c ==，您没有检查它是否为零。但是我也不明白你想做什么，没有使用"c“可验证，对于"subtruction.hpp”也是如此，为什么还要检查"c“呢？
最后一件事，你的风格是不一致的，注意这一点(不重要的实际，但不是那么容易阅读)。
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原文链接：
https://codereview.stackexchange.com/questions/156307
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