'class std::vector<indiv>' has no member named 'init_PM'

[phalangium]

I am getting the above compiler error when I try to run the following code:

#include <iostream>
#include <vector>
using namespace std;

class indiv {
// data members
// functions
public:
int init_PM(indiv &PM, int m, int chr, int z);		// declaration of init_PM as a member function of class indiv
//other functions
};

int indiv::init_PM(indiv &PM, int m, int chr, int z)	// definition of init_PM as a member function of class indiv
{z=5;
return z;}

int main()
{
int init_PM(indiv PM, int m, int chr, int z);		// init_PM declared in main()
int m=2;			// set by 'cin>>' in full program
int chr=19;			// set by 'cin>>' in full program
int z=0;
// other declarations

vector<indiv> PM(m);		// create a vector of m* indiv data-types
z=PM.init_PM(PM, m, chr, z);				// init_PM called; <<<<<<<< compiler error points to this line
cout<<"z now = "<<z<<endl;	// to prove that z has changed to 5

// rest of main
}

I wondered at first if this was a problem with passing the vector as this is new to me, but removing the vector parameter makes no difference. (I have also checked that my "&"s match the example code given in https://www.geeksforgeeks.org/passing-vector-function-cpp/).

I tried adding "indiv::" before the declaration in main() and this just made matters worse (I got additional errors).

It's telling me that there is no member called init_PM in indiv, but,
as far as I can see, I have both declared and defined init_PM() as a member function of class indiv, and declared it at the beginning of main().

I am sure that I am making some incredibly basic (=stupid) mistake, but I cannot for the life of me see what it is. Please, can anyone see what I am doing wrong?

Thanks.

[Peter87]

PM is a vector<indiv> which doesn't have a init_PM function.

Did you perhaps mean to call init_PM on one of the m indiv objects in PM (which one?).

// calls init_PM on the first vector element and passes the second vector element as argument.
z = PM[0].init_PM(PM[1], m, chr, z);

[phalangium]

Thanks for the reply, Peter87.

I knew it was going to be something stupid.

In the full program, init_PM() sets the intial values for each member of the vector, so I am going to have to call it for each of the m members.

I have replaced lines 26 & 27 with:

for(x=0; x<m; x++){
	z=PM[x].init_PM(PM[x], m, chr, z);
	cout<<"returned from init_PM("<<x<<"): "<<z<<endl;

and tested it. It appears to be performing as required.

Thanks.

[Peter87]

There is not really much point in the first parameter if you are always going to pass the same object that the function is called on.

z=PM[x].init_PM(PM[x], m, chr, z);
    ^             ^
  These two always the same?

In C++ we normally use constructors to initialize class objects. It's another alternative that you might want to consider.

[phalangium]

Thanks for the suggestions.

I tried removing the first parameter and got another error from within init_PM(). This may well be because the function is considerably more complicated than the version I put in the code above, calling other functions like:

PM.expand(chr);

the compiler told me that 'PM was not declared in this scope'. Although it was happy enough with other functions like PM.set_values(chr, z) and PM.print_out(chr) inside init_PM()!

I will have a look at constructors. This is really my first serious attempt to build a class and I am rather learning the process as I go along. So far I haven't really considered constructors beyond a default one to make sure I have something to put data into when I have created an instance of my class. Your suggestion is a good excuse for me to investigate them further.

Thanks.