bug {was not declared in this scope}

使用自己定义的结构体作为返回值的时候，出现了

。。。was not declared in this scope

检查了各种头文件，把缓存也都删掉了还是不行。

结果，发现，应该这样用vector<MyClass:: myStruct>

 error: ‘particle’ was not declared in this scope
 vector<particle> Pfloc::pf_init_particles(particle* particles,unsigned x0,unsigned y0)
        ^
/home/xy/code/pfloc_ubuntu/src/pfloc.cpp:56:16: error: template argument 1 is invalid
 vector<particle> Pfloc::pf_init_particles(particle* particles,unsigned x0,unsigned y0)
                ^
/home/xy/code/pfloc_ubuntu/src/pfloc.cpp:56:16: error: template argument 2 is invalid
/home/xy/code/pfloc_ubuntu/src/pfloc.cpp:56:18: error: prototype for ‘int Pfloc::pf_init_particles(Pfloc::particle*, unsigned int, unsigned int)’ does not match any in class ‘Pfloc’
 vector<particle> Pfloc::pf_init_particles(particle* particles,unsigned x0,unsigned y0)
                  ^
In file included from /home/xy/code/pfloc_ubuntu/src/pfloc.cpp:1:0:
/home/xy/code/pfloc_ubuntu/include/pfloc.h:44:19: error: candidate is: std::vector<Pfloc::particle> Pfloc::pf_init_particles(Pfloc::particle*, unsigned int, unsigned int)
  vector<particle> pf_init_particles(particle* p,unsigned x0, unsigned y0);
                   ^
/home/xy/code/pfloc_ubuntu/include/pfloc.h:32:4: error: ‘typedef struct Pfloc::particle Pfloc::particle’ is private
  } particle;
    ^
/home/xy/code/pfloc_ubuntu/src/pfloc.cpp:56:43: error: within this context
 vector<particle> Pfloc::pf_init_particles(particle* particles,unsigned x0,unsigned y0)