Question

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

void scan_data(char&, float&);
void do_next_op(char, float, float&);

int main()
{
    float accumulator; //value on the left of the equation
    float operand; //value on the right
    char op = ' ';

    while(op != 'q')
    {
        scan_data(op, operand); //retrieve the operator and operand from the file
        do_next_op(op, operand, accumulator);
        if (op != 'q')
        {
            cout << "Result so far is " << setprecision(1) << fixed << accumulator;
        }
        else
        {
            return 1;
        }
    }


    return 0;
}

void scan_data(char& op, float& operand)
{
    cin >> op >> operand;
}

void do_next_op(char op, float operand, float& accumulator)
{
    if (op == '+')
    {
        accumulator = accumulator + operand;

    }
    else if (op == '-')
    {
        accumulator = accumulator - operand;
    }
    else if (op == '*')
    {
        accumulator = accumulator * operand;
    }
    else if (op == '/')
    {
        if (operand != 0)
        {
            accumulator = accumulator / operand;
            cout << "Result so far is " << fixed << setprecision(1) << accumulator << endl;
        }
        else
        {
            cout << "Error: Division by zero";
        }
    }
    else if (op == '^')
    {
        accumulator = pow(accumulator, operand);
    }
    else if (op == 'q')
    {
        cout << "Final result is " << accumulator << ".";
    }
    else
    {
        cout << "Error: invalid operator" << endl;
    }
}

虽然xcode没有告诉我语法有什么问题，但我无法运行。你们能指出我如何让它运行的正确方向吗？

Answer 1

语法没有错，因为我能够在VS2013上运行它。您需要初始化累加器（浮点累加器（0））以获得任何有意义的计算。

您还应添加一些内容以提示用户在scan_data函数中输入操作数和操作数。

最后你应该在用户输入之后测试q，而不是强迫他们输入'q'然后输入另一个数字，这取决于你对程序的用途。

void scan_data(char& op, float& operand)
{
    cin >> op;
    if(op == 'q')
        return;

    cin >> operand;
}

使用cin在函数中通过引用传递2个值时遇到问题

1 个答案: