数学导师计划的烦恼

Question

您好再次堆栈溢出用户！我有一个新程序，但又遇到了一个我无法弄清楚的问题！我写了一个程序，数学导师程序，实​​际上已经完成了，只是有些东西我想不通。在程序中，有一个 void 函数可以检查答案（如果用户输入正确或不正确，将显示）但我似乎无法让它工作。当我在我的 doOneSet void 函数中有它时（确实是一组或问题），即使答案是正确的，它似乎也只显示“不正确”？我似乎无法弄清楚我做错了什么或缺少了什么。感谢任何类型的帮助/提示/参考。谢谢！

#include <iostream>
#include <ctime>
#include <cstdlib>

using namespace std;

void getProbsPerSet (int& numProbs);
void printHeader (/*in*/ char problemType);
void getMaxNum(/* out */int& maxNum);
void generateOperands(int& num1, int& num2, int maxNum);
void checkAnswer (/* in */int num1,/* in */ int num2, /*out*/ int& answer);
void calcCorrectAnswer(/* in */ char problemType,/* in */ int num1,/* in */int num2, /*inout*/ int& answer);
void doOneProblem (char problemType, int maxNum);
void doOneSet (char problemType, int probsPerSet, int&);
void printReport (/* in */ int probsPerSet, int& set1Correct, /* in */int& set2Correct, /* in */int& set3Correct);

int main ()

{

    int set1Correct, set2Correct, set3Correct, probsPerSet, maxNum;

    srand(time(0));
    getProbsPerSet (probsPerSet);
    cout << endl;
    doOneSet ('+', probsPerSet, set1Correct);
    cout << endl;
    doOneSet ('-', probsPerSet, set2Correct);
    cout << endl;
    doOneSet ('*', probsPerSet, set3Correct);
    cout << endl;

    return 0;   
}

void getProbsPerSet (int& numProbs)
{   
    cout << "Enter problems per set: ";
    cin >> numProbs;
    cout << endl;

    while (numProbs < 3 || numProbs > 10)
    {
        cout << endl;
        cout << "Please stay between 3 and 10. Thank you!";
        cout << endl;
        cout << endl;
        cout << "Enter problems per set: ";
        cin >> numProbs;
        cout << endl;
    }   

}

void printHeader (/*in*/ char problemType)
{
    switch(problemType)
    {
        case  '+': cout << endl;
                   cout << "Set # 1" << endl;
                   cout << "----------" << endl;
                break;

        case  '-': cout << endl;
                   cout << "Set # 2" << endl;
                   cout << "----------" << endl;
                break;

        case  '*': cout << endl;
                   cout << "Set # 3" << endl;
                   cout << " ----------" << endl;
                break;
    }
}

void doOneProblem (char problemType, int maxNum)

{
    int num1,num2,answer;

    generateOperands(num1, num2, maxNum);

    switch (problemType)
            {

                    case  '+' : cout << num1 << problemType << num2 << " = ";
                                cin >> answer;
                                break;

                    case  '-' : cout << num1 << problemType << num2 << " = ";
                                cin >> answer;
                                break;

                    case  '*' : cout << num1 << problemType << num2 << " = ";
                                cin >> answer;
                                break;
            }
}

void doOneSet (char problemType, int probsPerSet, int& answer)
{
    int num1, num2, numProbs, maxNum;
    bool isCorrect;

    printHeader(problemType);
    getMaxNum(maxNum);

    for (int count = 0; count < probsPerSet; count++)
    {   
        generateOperands(num1, num2, maxNum);
        doOneProblem (problemType, maxNum);
        calcCorrectAnswer(problemType, num1, num2, answer);
        checkAnswer (num1, num2, answer);
    }
}

void generateOperands(int& num1, int& num2, int maxNum)
{
        num1 = 1 + rand() % maxNum;
        num2 = 1 + rand() % maxNum;
}

void getMaxNum(/*out*/ int& maxNum)

{
    cout << "What is the maximum number for this set?: ";
    cin >> maxNum;
}

void checkAnswer (int num1, int num2, /*out*/ int& answer)
{
    bool isCorrect;

    if (answer == isCorrect)
    {
        cout << endl;
        cout << "Correct!" << endl;
        cout << endl;
    }
    else 
    {
        cout << endl;
        cout << "Incorrect!" << endl;
        cout << endl;
    }
}

void calcCorrectAnswer(/* in */ char problemType,/* in */ int num1,/* in */int num2, /*inout*/ int& answer)
{
    bool isCorrect;

    switch (problemType)
        {

                case  '+' : isCorrect = num1 + num2;
                            break;

                case  '-' : isCorrect = num1 - num2;
                            break;

                case  '*' : isCorrect = num1 * num2;
                            break;
        }
}

void printReport (/* in */ int probsPerSet, int& set1Correct, /*in*/ int& set2Correct, /*in*/ int& set3Correct)
{
    int set1Percent = 0, set2Percent = 0, set3Percent = 0;
    int total, complete;
    int numcorrect = 1;

    total = set1Correct + set2Correct + set3Correct;

    complete = probsPerSet + probsPerSet + probsPerSet;

    set1Percent = (100 * set1Correct) / probsPerSet;
    set2Percent = (100 * set2Correct) / probsPerSet;
    set3Percent = (100 * set3Correct) / probsPerSet;

    cout << endl;
    cout << "Set #1 : You got " << set1Correct << " correct out of " << probsPerSet << " for " << set1Percent << "%" << endl;
    cout << "Set #2 : You got " << set2Correct << " correct out of " << probsPerSet << " for " << set2Percent << "%" << endl;
    cout << "Set #3 : You got " << set3Correct << " correct out of " << probsPerSet << " for " << set3Percent << "%" << endl;
    cout << endl;
    cout << "Overall you got " << total << " out of " << complete << endl;;
}

Answer 1

问题是你的bool isCorrect;。两个都。 ?

因此，在一个函数calcCorrectAnswer 中，您声明了这个变量，然后根据您的需求逻辑对其进行设置。很好。

然后在另一个函数checkAnswer 中再次声明它，然后将其与true/false 进行比较以选择要生成的输出。

但是这些是不同的变量。尽管共享一个名称，但它们的范围仅限于它们所在的功能，因此设置一个对另一个没有影响。 checkAnswer 中的那个是未初始化的，从不带值，所以你的程序有未定义的行为。

您可以从calcCorrectAnswer 返回您的布尔值并将其作为参数传递给checkAnswer。或者你可以合并这两个函数；将它们分开似乎没有什么重要的理由。