Question

#include "stdafx.h"
#include <iostream>
#include <iomanip>
using namespace std;

int main()
{
    double tuitionCalc(int sumCreditHoursTaken);    //function prototype

    double tuitionCost;
    double creditHours;
    int numCourses;
    int count;
    int sumCreditHoursTaken = 0;

    cout << "       This program calculates a students total number of\n\n";
    cout << "       credit hours and tuition for a given semester.\n\n\n";

    cout << "Please enter the amount of courses you will be taking this semester: ";
    cin >> numCourses;

    for (count = 1; count <= numCourses; count++)   //for loop to find the total credit hours taken
    {
        cout << "\nPlease enter the number of credit hours for class " << count << ": ";
        cin >> creditHours;
        sumCreditHoursTaken += creditHours;
    }

    cout << "\n\nYour total number of credit hours taken is: " << sumCreditHoursTaken << "\n\n";
    cout << "Your total tuition will be: $" << tuitionCalc(tuitionCost) << "\n\n";

    system("PAUSE");
    return 0;
}

它说问题发生在我尝试调用函数tuitionCalc()的上方。

这是我试图打电话的功能：

double tuitionCalc(int sumCreditHoursTaken)
{
    double tuitionCost = 0;                                                                         
    double costCreditHour = 147.00;
    double maintFeeAddOn = 29.33;
    int maxHoursFullTuition = 12;

    if (sumCreditHoursTaken <= maxHoursFullTuition)
        sumCreditHoursTaken * costCreditHour;
    else
        (maxHoursFullTuition * costCreditHour) + ((sumCreditHoursTaken - maxHoursFullTuition) * maintFeeAddOn);

    return tuitionCost;
}

Answer 1

在第

行

cout << "Your total tuition will be: $" << tuitionCalc(tuitionCost) << "\n\n";

您将函数tuitionCalc与未初始化的参数tuitionCost一起使用。所以编译器试图警告你。这是技术上未定义的行为。您需要确保传递给函数的任何内容都具有明确定义的值。在您的情况下，因为tuitionCost未初始化，您传递的任何垃圾值恰好存储在内存位置&tuitionCost。请记住，C ++ 不会将变量初始化为零。如果按值将它们传递给函数，则需要手动初始化它们。我的猜测是你实际上想要将sumCreditHoursTaken（你刚刚在函数调用之上计算）传递给tuitionCalc函数。

Answer 2

您将tuitionCost的值传递给tuitionCalc方法，但您没有在tuitionCost中添加任何内容。由于变量是在本地声明的，因此它将具有随机值。编译器希望您知道。

C4700：未初始化的本地变量＆＃39; tuitionCost＆＃39;

2 个答案: