错误：'varName'未在此范围中声明 [英] error: 'varName' was not declared in this scope

问题描述

我想在我的图像中找到更大的轮廓（使用opencv和C ++）。我已经读过这个线程：
在OpenCV中查找轮廓？和绘制最大的元素连接使用areaContours（OpenCV）但我得到错误： 'varName'没有在这个范围内声明，这意味着编译器认为我还没有声明这个变量对吗？所以我的代码片段：

I want to find the biggerst contour in my image (with opencv and C++). I have been read this thread: Finding Contours in OpenCV? and Draw the biggest element conncted using areaContours (OpenCV ) but I got error: 'varName' was not declared in this scope, which mean compiler think I haven't been declare that variable right? So this snippet of my code:

    threshold(Img, Img, t, 255, CV_THRESH_BINARY_INV);
    vector<vector<Point>> varName;
    findContours(Img, varName, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE);

我遇到此错误：

   D:\OpencvWorkspace\....|50|error: 'varName' was not declared in this scope|

第50行是此代码：

    vector<vector<Point>> varName;

我的问题。为什么编译器问这个变量没有声明在行声明那个变量。

My question. Why compiler ask this variable haven't declare at the line I declare that variable. could someone help me?

推荐答案

您使用了一个pre c ++ 11标准编译器（如您的意见）。较老的标准有一个问题，让解析器消除在嵌套模板类型说明符中使用的一对闭包括号>> ，从 operator> ;>（）。因此，你必须在它们之间写一个空格：

You have used a pre c++11 standard compiler (as proven in your comment). The older standard had a problem letting the parser disambiguate a pair of closing angle brackets >> used in a nested template type specifier, from the operator>>(). Thus you had to write a space between them:

vector<vector<Point> > varName;
                 // ^ Note the space

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