Question

`void calc_distance（vector fingerTips，CvPoint palmCenter，IplImage * source） { 双倍距离= 0;

vector<CvPoint>::iterator p;

if (fingerTips.size() != NULL && fingerTips.size() <= 5 && fingerTips.size()  >= 1)
{   

    if ((fingerTips.size() > 1) || (fingerTips.size() <= 5))
        {

        distance = 0;

        p = fingerTips.begin();

        CvPoint forefinger = *p;

        CvPoint secondfinger;

        for( ;p != fingerTips.end(); )
                    {

                           p++; 

                           secondfinger = *p;

               distance +=  sqrt(double((forefinger.x - secondfinger.x) *

（forefinger.x - secondfinger.x）+（forefinger.y - secondfinger.y）*（forefinger.y - secondfinger.y）））;

                cvLine(source,forefinger,secondfinger,cvScalar(1.0,1.0,1.0),3,8);

                forefinger = secondfinger;

            }
                    }
     }

}

//作为参数我传递了指尖坐标的矢量和手掌的中心以及图像源但仍然得到错误：“矢量迭代器不是不同的”.... 错误发生在第二次迭代“secondfinger = * p;”线..... 请帮帮我......

在这里，我试图获得每个手指之间的距离，并将每个手指相加最后的距离......

请帮帮我......

Answer 1

您检查p != end，然后P++，然后取消引用。你应该只为循环做一个标准：

for(; p != fingerTips.end(); p++)
{
    //p++ //This is gone now. It's up in the for loop
   ...
}

而不是在for循环中使用p++

Answer 2

在递增之前，您需要取消引用p;否则，当你到达集合的末尾时，你最终会尝试取消引用fingertips.end()，这是无法解除引用的。

for( ;p != fingerTips.end(); ++p)
{
    secondfinger = *p;

    distance +=  sqrt(double((forefinger.x - secondfinger.x) * (forefinger.x - secondfinger.x) + (forefinger.y - secondfinger.y) * (forefinger.y - secondfinger.y)) );

    cvLine(source,forefinger,secondfinger,cvScalar(1.0,1.0,1.0),3,8);

    forefinger = secondfinger;

}

矢量迭代器不是dereferencable ....？

2 个答案: