Segmentation Fault Debug

This is a discussion on Segmentation Fault Debug within the C++ Programming forums, part of the General Programming Boards category; I have ended up running into a specific problem in my own C++ project which is now crashing (throwing a ...

  1. #1
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    Segmentation Fault Debug

    I have ended up running into a specific problem in my own C++ project which is now crashing (throwing a segmentation fault error). I have created an entire project, which I have pasted below, which essentially recreates all of the code/classes/methods that are related to the segmentation fault error in as simple a form as possible. The project below behaves in exactly the same way as my more complicated personal project in that:
    1. it crashes due to a segmentation fault, and
    2. it runs successfully if the datatype used throughout the project is switched to being an integer instead of a string.

    Does anyone have a clue why this would be? I am a lost, beginner programmer, and the error/debugger messages in Codeblocks are not helping me out much (although I don't exactly know for what to look--emphasis on beginner programmer).

    An idea of what the code is doing in general: I have an array of child objects stored within a parent object. Every child object has a single attribute of type string. I want to be able to retrieve ("get") that attribute value of a specific child object stored within a given parent object, passing the "child objects array" index as a parameter.

    main.cc
    Code:
    #include <iostream>
    #include "parent.h"
    
    int main() {
      Parent ParentObject;
      std::cout << ParentObject.BadassGetObjectAttribute(5) << std::endl;
    }
    parent.cc
    Code:
    #include "parent.h"
    
    std::string Parent::BadassGetObjectAttribute(int x) {
      array_of_children[x].GetObjectAttribute();
    }
    parent.h
    Code:
    #ifndef PARENT_H
    #define PARENT_H
    
    #include "child.h"
    
    class Parent {
     public:
      std::string BadassGetObjectAttribute(int);
    
     private:
      Child array_of_children[20];
    };
    
    #endif
    child.cc
    Code:
    #include "child.h"
    
    Child::Child() {
      object_attribute = "this string is initialized";
    }
    
    std::string Child::GetObjectAttribute() {
      return object_attribute;
    }
    child.h
    Code:
    #ifndef CHILD_H
    #define CHILD_H
    
    #include <string>
    
    class Child {
     public:
      Child();
      std::string GetObjectAttribute();
    
     private:
      std::string object_attribute;
    };
    
    #endif

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    Your compiler should be complaining bitterly about this function:
    Code:
    std::string Parent::BadassGetObjectAttribute(int x) {
      array_of_children[x].GetObjectAttribute();
    }
    Probably something like "not all paths return a value". In fact no path returns a value, because nothing is returned from this function. You should probably return your string you get from GetObjectAttribute.

  3. #3
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    Don't know why the compiler doesn't complain about that. Somehow, integer datatypes actually work perfectly in the code as written.

    The correct code, as you mentioned should be:
    Code:
    std::string Parent::BadassGetObjectAttribute(int x) {
      return array_of_children[x].GetObjectAttribute();
    }
    Thanks for the quick review.

  4. #4
    and the Hat of Guessing tabstop's Avatar
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    Quote Originally Posted by nair View Post
    Don't know why the compiler doesn't complain about that.
    The reason is probably "you turned off compiler warnings". In Code::Blocks, you go to Settings->Compiler and Debugger and you get a bunch of options. You want to check at least the ones that say -Wall and -Wextra. If you want to use the debugger, you'll need to make sure -g is checked. There's probably no reason not to check -pedantic too.

  5. #5
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    You are correct. Every flag in my "Compiler Settings" was unchecked.

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