C++ vector pointer array

Question

have struct_gene and struct_units. i read all Struck_gene values to vector. How do i assign pointer for struck_units.has_gene[i] to point to some value in struct_genevector so i dont have to write full copy of stuckt_gene And after that read it.

I tried for some time but didn't manage to get working solution

http://a.imageshack.us/img195/8607/001tfa.jpg

Edit - Here's the code as retrieved by Jakobud:

#include <iostream>
#include <fstream>
#include <vector>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>

using namespace std;
struct struct_gene {
    string name;
    string description;
};

struct struct_unit {
    string name;
    string surname;
    int age;
    int hunger;
    int happines;
    vector<struct_gene> *has_genes[12];
    struct_unit *maried_to;
    struct_unit *father;
    struct_unit *mother;
};

int main () {
    const int default_unit_count = 4;
    fstream gene_list;
    struct_gene * t_struct_gene;
    t_struct_gene = new struct_gene;
    gene_list.open("gene_list", ios::in);
    vector<struct_gene> vector_gene;
    //string name, description;

    gene_list >> t_struct_gene->name;
    getline(gene_list, t_struct_gene->description);
    while (gene_list) {
        vector_gene.push_back(*t_struct_gene);
        gene_list >> t_struct_gene->name;
        getline(gene_list, t_struct_gene->description);
    }
    delete t_struct_gene;

//   for (int i =0; i<vector_gene.size(); i++) {
//      cout <<vector_gene[i].name <<" "<<vector_gene[i].description<<endl;
//   }
    struct_unit *t_struct_unit;
    t_struct_unit = new struct_unit;

    srand ( time(NULL) );

    vector<struct_unit> vector_units;

    for (int i=0; i<default_unit_count; i++) {

        t_struct_unit->name = "unit_name";
        t_struct_unit->surname = "unit_surname";
        t_struct_unit->age = rand()%200;
        t_struct_unit->hunger = rand()%70 +30;
        t_struct_unit->happines = rand()%70 + 30;
        for (int i=0; i<12; i++) {
            t_struct_unit->has_genes[i] = vector_gene[rand()%vector_gene.size()];
        }
        t_struct_unit->maried_to = NULL;
        t_struct_unit->father = NULL;
        t_struct_unit->mother = NULL;
        vector_units.push_back(*t_struct_unit);
    }

    for (int i=0; i<vector_units.size(); i++) {
        cout << vector_units[i].name <<" "<<vector_units[i].surname<<endl;
        cout <<"Age:"<< vector_units[i].age <<" Hunger:"<<vector_units[i].hunger<<" Happines:"<<vector_units[i].happines<<endl;
        for (int j=0; j<0; j++) {
            cout <<vector_units[i].has_genes[j].name;
        }
        cout <<"==="<<endl;
    }
    delete t_struct_unit;
}

Please paste your code into the question. There's a button that looks like "101 010" to format it as code. — Cogwheel
– Cogwheel, Commented Jul 14, 2010 at 1:31

Borealid · Accepted Answer · 2010-07-14 01:55:33Z

1

t_struct_unit->has_genes[i] = &vector_gene

This will assign a pointer to the your gene list into the unit's ith slot.

But beware, since vector_gene is not a global variable, it (and all its contents) will be filled with garbage some time after the function it is in returns. Since it's in main, that's probably a non-issue for you, but you should know about the difference between stack and heap allocations.

Also, are you sure you want each struct_unit to hold a whole array of vectors of struct_genes? Don't you want each one to hold just twelve genes, rather than 12 vectors of genes?

edited Jul 14, 2010 at 1:55

answered Jul 14, 2010 at 1:40

Borealid

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3 Comments

kurrata Over a year ago

Right now it is in main because i am checking out how this stuff works. For later i plan to leave all vectors in main () and do operations to them thought functions

kurrata Over a year ago

tried this "t_struct_unit->has_genes[i] = &vector_gene[i]" and it didnt work. t_struct_unit->has_genes[i] = &vector_gene[rand()%vector_gene.size()];

Borealid Over a year ago

Sorry, you have only one gene vector. My mistake. Edited.

Tom · Accepted Answer · 2010-07-14 01:38:31Z

0

Try this;

1) instance struct_unit

struct_unit aunit;

2) Then inside the loop set the gene in the desired position (SOME_INDEX to be defined by you)

//inside loop
vector_gene.push_back(*t_struct_gene);
aunit.has_genes[SOME_INDEX] = *t_struct_gene;
//

answered Jul 14, 2010 at 1:38

Tom

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1 Comment

kurrata Over a year ago

Tried doing it this way to and it didn't work. t_struct_unit->has_genes[i] = *vector_gene[rand()%vector_gene.size()]

Jake Wilson · Accepted Answer · 2010-07-14 01:53:48Z

Here is his code:

#include <iostream>
#include <fstream>
#include <vector>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>

using namespace std;
struct struct_gene {
    string name;
    string description;
};

struct struct_unit {
    string name;
    string surname;
    int age;
    int hunger;
    int happines;
    vector<struct_gene> *has_genes[12];
    struct_unit *maried_to;
    struct_unit *father;
    struct_unit *mother;
};

int main () {
    const int default_unit_count = 4;
    fstream gene_list;
    struct_gene * t_struct_gene;
    t_struct_gene = new struct_gene;
    gene_list.open("gene_list", ios::in);
    vector<struct_gene> vector_gene;
    //string name, description;

    gene_list >> t_struct_gene->name;
    getline(gene_list, t_struct_gene->description);
    while (gene_list) {
        vector_gene.push_back(*t_struct_gene);
        gene_list >> t_struct_gene->name;
        getline(gene_list, t_struct_gene->description);
    }
    delete t_struct_gene;

//   for (int i =0; i<vector_gene.size(); i++) {
//      cout <<vector_gene[i].name <<" "<<vector_gene[i].description<<endl;
//   }
    struct_unit *t_struct_unit;
    t_struct_unit = new struct_unit;

    srand ( time(NULL) );

    vector<struct_unit> vector_units;

    for (int i=0; i<default_unit_count; i++) {

        t_struct_unit->name = "unit_name";
        t_struct_unit->surname = "unit_surname";
        t_struct_unit->age = rand()%200;
        t_struct_unit->hunger = rand()%70 +30;
        t_struct_unit->happines = rand()%70 + 30;
        for (int i=0; i<12; i++) {
            t_struct_unit->has_genes[i] = vector_gene[rand()%vector_gene.size()];
        }
        t_struct_unit->maried_to = NULL;
        t_struct_unit->father = NULL;
        t_struct_unit->mother = NULL;
        vector_units.push_back(*t_struct_unit);
    }

    for (int i=0; i<vector_units.size(); i++) {
        cout << vector_units[i].name <<" "<<vector_units[i].surname<<endl;
        cout <<"Age:"<< vector_units[i].age <<" Hunger:"<<vector_units[i].hunger<<" Happines:"<<vector_units[i].happines<<endl;
        for (int j=0; j<0; j++) {
            cout <<vector_units[i].has_genes[j].name;
        }
        cout <<"==="<<endl;
    }
    delete t_struct_unit;
}

RiaD · Accepted Answer · 2013-03-08 18:42:29Z

http://codepad.org/TZpNS59a:

#include <iostream>
#include <fstream>
#include <vector>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>

using namespace std;
struct struct_gene {
    string name;
    string description;
};

struct struct_unit {
    string name;
    string surname;
    int age;
    int hunger;
    int happines;
    vector<struct_gene> *has_genes[12];
    struct_unit *maried_to;
    struct_unit *father;
    struct_unit *mother;
};

int main () {
    const int default_unit_count = 4;
    fstream gene_list;
    struct_gene * t_struct_gene;
    t_struct_gene = new struct_gene;
    gene_list.open("gene_list", ios::in);
    vector<struct_gene> vector_gene;
    //string name, description;

    gene_list >> t_struct_gene->name;
    getline(gene_list, t_struct_gene->description);
    while (gene_list) {
        vector_gene.push_back(*t_struct_gene);
        gene_list >> t_struct_gene->name;
        getline(gene_list, t_struct_gene->description);
    }
    delete t_struct_gene;

//   for (int i =0; i<vector_gene.size(); i++) {
//      cout <<vector_gene[i].name <<" "<<vector_gene[i].description<<endl;
//   }
    struct_unit *t_struct_unit;
    t_struct_unit = new struct_unit;

    srand ( time(NULL) );

    vector<struct_unit> vector_units;

    for (int i=0; i<default_unit_count; i++) {

        t_struct_unit->name = "unit_name";
        t_struct_unit->surname = "unit_surname";
        t_struct_unit->age = rand()%200;
        t_struct_unit->hunger = rand()%70 +30;
        t_struct_unit->happines = rand()%70 + 30;
        for (int i=0; i<12; i++) {
            t_struct_unit->has_genes[i] = vector_gene[rand()%vector_gene.size()];
        }
        t_struct_unit->maried_to = NULL;
        t_struct_unit->father = NULL;
        t_struct_unit->mother = NULL;
        vector_units.push_back(*t_struct_unit);
    }

    for (int i=0; i<vector_units.size(); i++) {
        cout << vector_units[i].name <<" "<<vector_units[i].surname<<endl;
        cout <<"Age:"<< vector_units[i].age <<" Hunger:"<<vector_units[i].hunger<<" Happines:"<<vector_units[i].happines<<endl;
        for (int j=0; j<0; j++) {
            cout <<vector_units[i].has_genes[j].name;
        }
        cout <<"==="<<endl;
    }
    delete t_struct_unit;
}

line 62 is where i am trying to write pointer to stuct_gene vector

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