Question

我正在尝试从函数返回一个值，该函数有一个参数，我只是不知道如何获取这些值。我知道我可能做了一些错误的代码，这就是我在这里的原因。

以下是代码：

    // ask user if male or female
// complete calculations depending on result 
// ask user for: weight in lbs, height in inches and age. 

#include <iostream>

// function for users height in inches
double usersHeight(double height)
{
    return height; 
}

//function for users age
int usersAge(int age)
{
    return age; 
}

// function for users weight in lbs
double usersWeight(double weight)
{
    return weight;
}

// mens bmr (basal metabolic rate)
double calculateBmrForMen()
{
    // return calculations
    // Men: BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years)
    double BMR = 66 + (6.23 * usersWeight(weight/*how do I get user input and here without causing any errors?*/)) 
                    + (12.7 * usersHeight(height/* and here*/))
                    - (6.8 * usersAge(age/*and here*/));
    return BMR; 
}

// womens bmr
double calculateBmrForWomen()
{
    // return calculations
    // Women: BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)

    double BMR = 655 + (4.35 * usersWeight()) + (4.7 * usersHeight()) - (4.7 * usersAge());
    return BMR; 
}

int main()
{
    /*char a; 

    std::cout << "Are you Male or Female: " << std::endl;
    std::cout << "Press M if Male\nPress F if female" << std::endl;
    std::cin >> a; 

    if (a == 'm') 
    {
        calculateBmrForMen(); 
    }
    else if (a == 'f')
    {
        calculateBmrForWomen(); 
    }*/

    std::cin.get(); 
    std::cin.clear();
}

Answer 1

看看你如何使用这些函数，我猜你想提示用户在函数userAge中输入用户的年龄并将该值返回给调用函数。

如果那是你想做的......

这是你的功能应该是什么样的。

int usersAge()
{
    int age;
    std::cout << "Please enter age: ";
    std::cin >> age;

    // If the user entered incorrect data, try again.
    if ( !std::cin )
    {
       std::cout << "Unable to read age. Try again.\n";
       std::cin.clear();
       std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
       return userAge();
    }

    return age; 
}

确保添加

#include <limits>

能够使用std::numeric_limits。

对其他功能进行类似的更改。

Answer 2

请修改您的代码如下; 希望这会有所帮助。

double usersHeight()
{
    double height;
    cout << "Ënter Height..." << endl;
    cin >> height; 
    return height;
}

//function for users age
int usersAge()
{
    int age;
    cout << "Ënter age..." << endl;
    cin >> age; 
    return age;
}

// function for users weight in lbs
double usersWeight()
{
    double weight;
    cout << "Ënter weight..." << endl;
    cin >> weight; 
    return weight;
}


double calculateBmrForMen()
{
    // return calculations
    // Men: BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years)
    double BMR = 66 + (6.23 * usersWeight()) 
                    + (12.7 * usersHeight())
                    - (6.8 * usersAge());
    return BMR; 
}

// womens bmr
double calculateBmrForWomen()
{
    // return calculations
    // Women: BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)

    double BMR = 655 + (4.35 * usersWeight()) + (4.7 * usersHeight()) - (4.7 * usersAge());
    return BMR; 
}

int main()
{
    char a; 
    double BMI;
    std::cout << "Are you Male or Female: " << std::endl;
    std::cout << "Press M if Male\nPress F if female" << std::endl;
    std::cin >> a; 
    if (a == 'm') 
    {
        BMI = calculateBmrForMen(); 
    }
    else if (a == 'f')
    {
        BMI = calculateBmrForWomen(); 
    }

    cout << "The BMI is..."<< BMI << endl;
    std::cin.get(); 
    std::cin.clear();
}

返回参数并在其他函数中使用它们

2 个答案: