c++ - 获取标识符选择未定义

Question

我正在开发一个计算器控制台应用程序。我是 C++ 的初学者，我希望程序在打印完之前的结果后提出问题。我收到以下错误，但我不知道如何修复它。

identifier "choice" is undefined

这是我的源代码:

#include "stdafx.h"
#include <iostream>

int getUserInput() {

    std::cout << "Please enter an integer: ";
    int value;
    std::cin >> value;
    return value;
}

int getConversionFormula() {

    std::cout << "What do you want to convert? (1 for Meters to feet, 2 for kilometers to miles, 3 for kilagrams to pounds.): ";

    int op;

    std::cin >> op;

    //user might select an invalid operation that isnt there
    //Implement a way to avoid this. 
    return op;
}

int getUserInput2() {
    std::cout << "Do you want to convert anything else? (hit 1 for yes, hit 2 for no): ";

    int choice; //for the user if they hit yes or no to the question above.

    std::cin >> choice;

    return choice;
}

int getUserChoice(int choice) {

    //If user selects 1 show the converstion formula screen
    if (choice == 1)
        getConversionFormula();
    if (choice == 2)
        std::exit;

    return -1;
}

int calculateResult(int x, int op) {

    //we will use == to compare two variables to see if they are true or not 
    if (op == 1)
        return x * 3.280839895; //meters to feet
    if (op == 2)
        return x / 1.609344; //km to miles
    if (op == 3)
        return x * 2.2046; //kg to pounds

    return -1; //If the user entered an invalid operation
}

void printResult(int result) {

    std::cout << "Your result is: " << result << std::endl;
}
int main()
{
    int input1 = getUserInput();   //Gets the users input

    int op = getConversionFormula();

    int result = calculateResult(input1, op);

    printResult(result);

    int input2 = getUserInput2(); //Asks the user if they want to convert anything else

    int input3 = getUserChoice(input2, choice);
    std::cin.clear(); // reset any error flags
    std::cin.ignore(32767, '\n'); // ignore any characters in the input buffer until we find an enter character
    std::cin.get(); // get one more char from the user
}

有人可以告诉我如何解决吗？我在 main 函数中得到错误只是为了让大家知道。

Answer 1

choice 没有在 main 中声明，它只在 getUserInput2 中声明，它返回。 getUserChoice 甚至不需要两个参数，所以只需执行以下操作:

getUserChoice(input2);

^{您可以开始稍微链接您的函数调用，例如:getUserChoice(getUserInput2());，从而消除一些局部变量。}