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Storing data in Vector of Struct

theingar (8)
Hello,

I am writing a program using ROS Workspace. There is a structure of data and which is converted to std::vector in somewhere of the codes. I am trying to store the data gained from one of the getters back to the vector.

When I compile the program, there is an error saying "no match for 'operator='" for the line of codes in getBaseRangeToBogie function.

I have pasted the concerning parts of my coding. Could you please tell me how can I solve it?

Thanks in advance.

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#include <vector>

struct RangeVelocityStamped { 
  double range;
  double velocity;
  long timestamp;
};

std::vector<RangeVelocityStamped> rangeVelocityToBogiesFromBase(void);



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class Base
{
public:
    Base();
    void getRangeBaseToBogie(const std::shared_ptr<Simulator> &sim, std::vector<RangeVelocityStamped> &vec, Info &info);

private:
    RangeVelocityStamped baseToBogie;
};



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Base::Base()
{}

void Base::getRangeBaseToBogie(const std::shared_ptr<Simulator> &sim, std::vector<RangeVelocityStamped> &vec, Info &info)
{
    baseToBogie = sim->rangeVelocityToBogiesFromBase();
    vec.push_back(baseToBogie);
}

RangeVelocityStamped Base::getRangeBogieFromBase()
{
    return baseToBogie;
}
Last edited on
helios (17574)
It's [code], not [c0de]. We're not been l33t here.

What does Simulator::rangeVelocityToBogiesFromBase() return?
theingar (8)
It returns RangeVelocityStamped (the range in metres) which is
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struct RangeVelocityStamped {
  double range; 
  double velocity; 
  long timestamp;
};
helios (17574)
Well, then no idea. Can you post the entire error message from the compiler?
theingar (8)
The error message is as follows:

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/home/user/Desktop/pfms-2020a-TheingarAungThan/scratch/a3_skeleton/base.cpp:17: error: no match for ‘operator=’ (operand types are ‘RangeVelocityStamped’ and ‘std::vector<RangeVelocityStamped>’)
     baseToBogie = sim->rangeVelocityToBogiesFromBase();
                 ^
Last edited on
helios (17574)
Oh, now I see it. Simulator::rangeVelocityToBogiesFromBase() return an std::vector<RangeVelocityStamped> not a RangeVelocityStamped.

This:
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    baseToBogie = sim->rangeVelocityToBogiesFromBase();
    vec.push_back(baseToBogie);
doesn't make sense. rangeVelocityToBogiesFromBase() is returning multiple velocities and you're assuming that it returns a single velocity. You need to decide what to do with all of them. Do you want to append the velocities to vec? Which velocity should be assigned to baseToBogie?
theingar (8)
Oh, I see now. Thank you for your explanation. So, I changed the codes as the following. Could you please check and let me know that it is correct or not?

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#include <vector>

struct RangeVelocityStamped {
  double range; 
  double velocity; 
  long timestamp;
};

struct RangeVelocityStamped { 
  double range;
  double velocity;
  long timestamp;
};

std::vector<RangeVelocityStamped> rangeVelocityToBogiesFromBase(void);


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class Base
{
public:
    Base();
    void getRangeBaseToBogie(const std::shared_ptr<Simulator> &sim, std::vector<std::vector<RangeVelocityStamped>> &vec, Info &info);

private:
    std::vector<RangeVelocityStamped> baseToBogie;
};


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Base::Base()
{}

void Base::getRangeBaseToBogie(const std::shared_ptr<Simulator> &sim, std::vector<std::vector<RangeVelocityStamped>> &vec, Info &info)
{
    baseToBogie = sim->rangeVelocityToBogiesFromBase();
    vec.push_back(baseToBogie);
}

std::vector<RangeVelocityStamped> Base::getRangeBogieFromBase()
{
    return baseToBogie;
}
helios (17574)
As far as I can tell, that will compile, but is that really what you want the code to do?
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