调试和发布模式下的不同结果

发布于 2024-11-16 21:41:14 字数 641 浏览 3 评论 0原文

vector<double> pvec;

double firstnode=0.0;

for(iter2=svec.begin(); iter2!=svec.end(); iter2++)
{
    double price= 0.0;
    string sFiyat = iter2->substr(13);
    stringstream(sFiyat)>>price;
    price=log(price);

    if (iter2==iter)
    {
        firstnode = price;
    }
    price -= firstnode;

    pvec.push_back(price);
}

我得到了上面的代码，调试和发布模式有一个神奇的差异。该算法的目的是使向量的第一个元素等于0，然后求第一个元素与其他元素的对数之差。

在调试模式下，这给出了我想要的结果，并且向量的第一个元素始终等于零。但是当我切换到释放模式时，向量的第一个元素等于一些小数字，例如 8.86335e-019。

这还不是全部。当我输入“cout <<价格<< endl;”行时在“price=log(price);”行之后然后我从发布版本得到的结果与调试模式得到的结果相同。有什么解释吗？

原文

vector<double> pvec;

double firstnode=0.0;

for(iter2=svec.begin(); iter2!=svec.end(); iter2++)
{
    double price= 0.0;
    string sFiyat = iter2->substr(13);
    stringstream(sFiyat)>>price;
    price=log(price);

    if (iter2==iter)
    {
        firstnode = price;
    }
    price -= firstnode;

    pvec.push_back(price);
}

I got the code above and there is a miracalous difference in debug and release modes. The algorithm aims to make the first element of the vector equal to zero and then finds the differences of the logarithms of the first element with other elements.

In debug mode, this gives the result that I desire and the first element of the vector is always equal to zero. But when I switch to the release mode the first element of the vector is equal to some small number such as 8.86335e-019.

And that's not all. When I put the line "cout << price << endl;" after the line "price=log(price);" then the result I got from the release version is same with the one from the debug mode. Any explanations?

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