Question

我已经为项目编写了一些基本代码。我正在尝试使用键盘仿真器从RFID阅读器获取输入。以下是我的代码：

    #include <iostream>
#include <ios>
#include <iomanip>
#include <cmath>

using namespace std;


int main()
{
    char product; //declaring the variable for the switch/case
    int Pay = 0; //Declaring the variable Pay
    int Payment = 0;
    double Total = 0; // Declaring the Final Total variable
    double Subtotal = 0; // Declaring the variable Subtotal
    double Tax = 0; // Declaring the variable Tax
    int m = 0; //counts the amount of times milk is scanned
    int b = 0; //counts the amount of times beer is scanned
    int c = 0; //counts the amount of times candy bar is scanned
    int r = 0; //counts the amount of times rice is scanned


    cout << "Scan the product you desire to purchase: \n";//Asking user to input product purchasing
    cout << "When ready to checkout press the z button.\n\n\n"; //Telling user to press button z to pay

    while(Pay < 1) //Keeps in the loop until pay is increased to 1
    {
        getline(cin, product); //Taking input and assining to the variable product


            if(product == E007C02A55EF918D) 
            {
                cout << "6 pack of Budlight...........$6.49\n"; // If the button b is pushed displays
                Subtotal = Subtotal + Beer; // Calculates the Subtotal and stores it
                Tax = Beer * Taxrate + Tax; // Claculates the total Tax and stores it
                b++;
            }

            else if(product == E007C02A55EF937C)
            {
                cout << "Snickers Bar.................$0.99\n";// If the button c is pusehd displays
                Subtotal = Subtotal + Candy_Bar;
                Tax = Candy_Bar * Taxrate + Tax;
                c++;
            }

            else if(product == E007C02A554A7A8B)
            {
                cout << "1 Gallon of 2% Milk..........$3.99\n";//If the button m is pushed displays
                Subtotal = Subtotal + Milk;
                m++;
            }

            else if(product == E007C02A55CE0766)
            {
                cout << "Box of Brown Rice............$2.79\n";//If the button r is pushed displays
                Subtotal = Subtotal + Rice;
                r++;
            }

            else
            cout << "Invaild product. Please scan a different product.\n";

            if (product == 'z')
            Pay++; //When finished it increases pay to 1 to break the while loop


        Total = Subtotal + Tax; // Claculates the Total

    }

我正在使用MSVS 2010来编译此代码。使用此代码我无法编译，因为它说未定义E007C02A55EF918D。 E007C02A55EF918D是其中一个RFID标签的序列号，是我想要输入的。我知道我也遇到了getline函数的问题，但我更担心的是将序列号作为输入。

Answer 1

char对于单个字符来说足够大（它通常是8位数量，但不依赖于它）。

所以你的product变量只能容纳一个字符。

E007C02A55EF918D是一个标识符（因为它以字母开头，不被视为数字，因为它没有被引用，所以它不会被解释为字符串）。

如果您打算product并且这些序列号为64位数字，则需要将product更改为足以存储它们（例如uint64_t），并更改代码中的序列号是0x前缀的数字。您还必须更改输入法（getline需要字符串，因此您需要将该字符串转换为数字 - 例如，请参阅How to convert a number to string and vice versa in C++。

if (product == 0xABCD1234)

如果您将两者都缩进为字符串，则使用：

声明product

std::string product;

并引用（""）序列号。您还需要将最后一个测试更改为：

if (product == "z")
               ^ ^

您无法将std::string与单个char进行比较（'z'是char，"z"是C样式的0终止字符串）。

Answer 2

尝试在""中使用strcmp()代替==，例如

if (!strcmp("E007C02A55EF937C",product))

或

if (strcmp("E007C02A55EF937C",product)==0)

希望它对你有所帮助。

键盘模拟器的字符串输入帮助

2 个答案: