从类中引用typedef时“没有命名类型”错误

Question

I have the following definition of a typedef in a class

/*
 *ReportData.h
 */
class ReportData {

public:

    /** Classifiers information  **/
    typedef struct{ 
        char *classifier;
        uint8_t numCategories;
        char **categories;    
        int *ranges;          
    } Classification;
};

This code is later referenced as follows

/*
 * DynamicCarDetection.cpp 
 */

    #include <DataReport.h>

    int numOfClassGroups = 1;
    int numOfCategories = 2;
    ReportData::Classification *vehiclesClassificators;

    vehiclesClassificators = new ReportData::Classification[numOfClassGroups];

    vehiclesClassificators[i].numCategories = NumOfcategories;
    vehiclesClassificators[i].categories = new char *[numOfcategories];

When I try to compile with this command

g++ -c DynamicCarDetection.cpp -I ./

I get this error on each reference to vehiclesClassificators

DynamicCarDetection.cpp:12:1: error: 'vehiclesClassificators' does not name a type

Looks like an obvious error of name scoping, but I've struggling to understand what the problem is, because apparently, the typedef ReportData::Classification is being recognized.

Many thanks in advance

Answer 1

In C++, sentences (except some corner cases) must be part of a function body. And in your CPP file there are none, so the compiler gets confused about what you are doing.

#include <DataReport.h>

void DoThings()
{
    int numOfClassGroups = 1;
    //....
}