为什么方法不起作用? [英] Why methods don't work?

问题描述

我正在对计算器进行编程，例如当我选择第一个选项时，程序将停止.我不能输入任何数字. 我必须在代码中进行哪些更改才能使方法起作用? 我不知道该怎么办.

I'm programming a calculator and when I choose for example first option, program stops. I can't enter any numbers. What do I have to change in my code to make the methods work? I don't know what I have to do.

main.cpp:

#include "stdafx.h"
#include <iostream>
#include "Calculator.h"

using namespace std;

float Calculator::add()
{
    cout << "Enter 1 number: ";
    cin >> a;
    cout << "Enter 2 number: ";
    cin >> b;
    system("cls");

    cout << a + b << endl;

    return 0;
}

float Calculator::sub()
{
    cout << "Enter 1 number: ";
    cin >> a;
    cout << "Enter 2 number: ";
    cin >> b;
    system("cls");

    cout << a - b << endl;

    return 0;
}

float Calculator::mul()
{
    cout << "Enter 1 number: ";
    cin >> a;
    cout << "Enter 2 number: ";
    cin >> b;
    system("cls");

    cout << a*b << endl;

    return 0;
}

float Calculator::div()
{
    cout << "Enter 1 number: ";
    cin >> a;
    cout << "Enter 2 number: ";
    cin >> b;
    system("cls");

    cout << a / b << endl;

    return 0;
}

int main()
{
    int choose;

    Calculator k1;

    cout << "1.Add\n";
    cout << "2.Sub\n";
    cout << "3.Mul\n";
    cout << "4.Div\n";
    cout << "Choose: ";
    cin >> choose;

    if (choose == '1')
        k1.add();
    else if (choose == '2')
        k1.sub();
    else if (choose == '3')
        k1.mul();
    else if (choose == '4')
        k1.div();


    system("pause");
    return 0;
}

Calculator.h:

Calculator.h:

#pragma once
#ifndef Calculator_h
#define Calculator_h

class Calculator {
private:
    float a, b;
public:
    float add();
    float sub();
    float mul();
    float div();
};

#endif

推荐答案

您正在阅读将select作为一个整数:int choose;，因此您必须将其视为一个整数:

You are reading choose as an int: int choose; so you have to treat it as one:

if (choose == 1)
    k1.add();
else if (choose == 2)
    k1.sub();
else if (choose == 3)
    k1.mul();
else if (choose == 4)
    k1.div();

按要求说明:

if (choose == '1')

从语法上来讲，这并没有错，因为简单地C ++是隐式广播字符'1'为其 ASCII码，它是一个值49的整数.

This is not wrong syntactically speaking because simply C++ is casting implicitly the char '1' to its ASCII code which is an int of value 49.

您实际上是在执行以下操作:if (choose == 49)而不是if (choose == 1)

You were literally doing the following: if (choose == 49) instead of if (choose == 1)

这篇关于为什么方法不起作用?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！