c++ - 代码块中的奇怪逻辑

Question

#include <iostream>
#include <stdlib.h>
#include <iomanip>

using namespace std;

int main ()
{
    double x = 10000;
    double y = x*0.05;

    if(500 == 400+100)
        cout<<"asd1"<<endl;

    if(500 == 0.05*x)
        cout<<"asd2"<<endl;

    if(500 == y)
        cout<<"asd3"<<endl;

}

上面的代码应该打印所有三个asd1、asd2、asd3。正如预测的那样，Visual Studio 打印了所有三个。但是，我的代码块不会。它没有打印 asd2。我该如何解决这个问题？

Answer 1

将其更改为:

int main ()
{
    int x = 10000;
    int y = x*0.05;

    if(500 == 400+100)
        cout<<"asd1"<<endl;

    if(500 == int(0.05*x))
        cout<<"asd2"<<endl;

    if(500 == y)
        cout<<"asd3"<<endl;

}

并尝试阅读:http://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html