告诉我的计算器不要除以零

Question

我正在用 C++ 制作一个计算器，它工作正常，除非我除以零。所以我有一个 if 语句说当一个数字被零除时给出消息“错误除以买零”。但是程序仍然崩溃。

这是我的代码

#include <iostream>

using namespace std;

int main()
{
    int a, b, d, s;
    d == a/b

    cout << "Enter first number\n";
    cin >> a;
    cout << "Enter second number\n";
    cin >> b;
    cout << "Select the operation you want\n";
    cout << "1.Addition\n";
    cout << "2.Subtraction\n";
    cout << "3.Multiplication\n";
    cout << "4.Division\n";
    cin >> s;

    switch (s)
    {
    case 1: cout << "Addition Selected\n"; a+b << endl;    break;
    case 2: cout << "Subtraction Selected\n"; a-b << endl; break;
    case 3: cout << "Addition Selected\n"; a*b << endl;    break;
    case 4:
        if (b==0)
        {
            cout << "Error Divide by Zero"<< endl;
        }
        else
        {
            cout << d << endl;
        }
    break;
    default: cout << "Invalid Selection" << endl;
    }

    return 0;
}

在我选择一个操作时，它并没有说它被选中。

Answer 1

您的代码有很多语法错误。

也许这可以帮助你。这巧妙地避免了除以零并打印错误消息。

#include <iostream>
using namespace std;

int main() {
    int n1, n2, ans;
    char op;
    cin >> n1 >> op >> n2;
    switch (op) {
    case '+':
        ans = n1 + n2;
        break;
    case '-':
        ans = n1 - n2;
        break;
    case '*':
        ans = n1 * n2;
        break;
    case '/':
        if (n2) {
            ans = n1 / n2;
            break;
        }
    default:
        cerr << "Invalid Input" << endl;
        return 1;
    }
    cout << ans;
    return 0;
}

参见http://ideone.com/wa8QJG 演示。

Answer 2

你的线路

d == a/b;

需要

d = a/b;

它需要在“else”子句中移动。否则在打印解释错误之前会出现除以 0 错误。

您还缺少拆分案例的印刷品，应该添加。

Answer 3

您的代码中有许多拼写错误/语法错误。

这是一个接近您的代码的可行解决方案：

int main()
{
    int a, b, d, s;

    cout << "Enter first number\n";
    cin >> a;
    cout << "Enter second number\n";
    cin >> b;
    cout << "Select the operation you want\n";
    cout << "1.Addition\n";
    cout << "2.Subtraction\n";
    cout << "3.Multiplication\n";
    cout << "4.Division\n";
    cin >> s;
    switch( s )
    {
    case 1:
        cout << "Addition Selected\n" << a + b << endl;
        break;
    case 2:
        cout << "Subtraction Selected\n" << a - b << endl;
        break;
    case 3:
        cout << "Multiplication Selected\n" << a * b << endl;
        break;
    case 4:
        if( b == 0 )
        {
            cout << "Error Divide by Zero" << endl;
        }
        else
        {
            d = a / b;
            cout << d << endl;
        }

        break;
    default:
        cout << "Invalid Selection" << endl;
    }
    return 0;
}