Question

下面的

是我在另一个.cpp文件中包含的.cpp文件。我收到一个错误，指出emp.grosPay（）必须是可修改的左值。关于修复它的任何想法？

 #include <iostream>
#include <string>
#include "weeklyEmp.h"

using namespace std;

const double WEEKLY_ALLOWANCE = 39.42;
const double FICA_TAX_RATE = 0.0765;
weeklyEmp::weeklyEmp()
{
    my_name = ?name?;
}
weeklyEmp::weeklyEmp(string initName,
    double initHours,
    double initRate,
    int initExemptions,
    string initFilingStatus)
{
    my_name; initName;
    my_hours; initHours;
    my_rate; initRate;
    my_exemptions; initExemptions;
    my_filingStatus; initFilingStatus;
}

//--modifiers

void weeklyEmp::set_hours(double thisWeeksHours)
    //post: Set the hours worked for a given week
{
    my_hours = thisWeeksHours;
}



void weeklyEmp::set_rate(double thisWeeksRate)
//post: Change the employee's hourly rate of pay
{
 my_rate = thisWeeksRate;
}

//--accessors
double weeklyEmp::grosPay() const
//post: Return gross pay with overtime

{if(my_hours <=40) return my_hours * my_rate;
else
return (40*my_rate) + (my_hours-40) * 1.5 * my_rate;
}

double weeklyEmp::incomeTax() const
//post: Return the federal income tax
{
double result(0.0);
double taxableIncome(grosPay() - my_exemptions * WEEKLY_ALLOWANCE); 
if(my_filingStatus == "S" || my_filingStatus == "s")
{
if (taxableIncome <= 23.00)
result = 0.00;
else if(taxableIncome <= 397.00)
result = 0.15 * (taxableIncome - 23.00);
else if(taxableIncome <= 928.00)
result = 56.10 + 0.28 * (taxableIncome - 397.00);
else if(taxableIncome <= 2121.00)
result = 204.78 + 0.33 * (taxableIncome - 928.00);
else
result = 598.47 + 0.28 * (taxableIncome - 2121.00);
} 
if(my_filingStatus == "M" || my_filingStatus == "m")
{
if(taxableIncome <= 65.00)
result = 0.00;
else if(taxableIncome <= 689.00)
result = 0.15 * (taxableIncome - 65.00);
else if(taxableIncome <= 1573.00)
result = 93.60 + 0.28 * (taxableIncome - 689.00);
else if(taxableIncome <= 3858.00)
result = 341.12 + 0.33 * (taxableIncome - 1573.00);
else
result = 1095.17 + 0.28 * (taxableIncome - 3858.00);
} 
/* round to the nearest penny */
/* include compfun.cpp for round function */
result =(result, 2);  
return result;
}

double weeklyEmp::FICATax() const
//post: Return the social security tax
{
    return grosPay() * FICA_TAX_RATE; 
}

string weeklyEmp::name() const
//post: Return the employee's name

{ return my_name;

}

带有错误的代码部分位于下方并标记为 * **

int main()
{
    string name;
    double rate;
    double hours;
    int exemptions;
    string filingStatus;


    cout <<"Name: ";
    cin >> name;
    cout << "Hourly Rate:";
    cin >> rate;
    cout << "Hours Worked:";
    cin >> hours;
    cout << "Exemptions: ";
    cin >> exemptions;
    cout<< "S) ingle / M) arried: ";
    cin >> filingStatus;
    cout << " " << endl;

    weeklyEmp emp(name, hours, rate, exemptions, filingStatus);
    double net = ***emp.grosPay()*** = emp.incomeTax() - emp.FICATax();

}

Answer 1

double net = emp.grosPay() = emp.incomeTax() - emp.FICATax();
//                        ^^^

grosPay没有返回引用，所以我假设您不打算在那里使用=符号。可能是一个滑动的拇指。

您的意思是使用减号运算符-？：

double net = emp.grosPay() - emp.incomeTax() - emp.FICATax();
//                        ^^^

发生错误是因为您无法修改const对象，const函数返回的对象或未绑定到非const rvalue-reference的rvalue。

Answer 2

double net = ***emp.grosPay()*** = emp.incomeTax() - emp.FICATax();
                                ^^^

第二个'='应该是' - '标志;我认为你试图减去，而不是分配。

必须是可修改的值错误？

2 个答案: