Segmentation fault with big array size. Why ?

Question

0.00/5 (No votes)

See more:

C++

struct person
{
char name[100];
int freq ;
} ;

I am creating an array of structure person and using this array as a hash table.

C++

int capacity;
struct person table[capacity] ;

I insert the string name by reading through a csv file which has a name on each of its line.

When I take table capacity to be around 50000 or more, a segmentation fault generates.

When I take a small capacity as 5000, everything works fine.

What if in my file there are around 60000 distinct names, How will I store them now ?

I don't understand why it is happening? Can it be because of my hash function?

I am using linear probing for finding hash value.

I am confused. Please help.

What I have tried:

I made the code in Netbeans IDE.

Posted 11-Oct-18 17:37pm

Member 13995616

Updated 12-Oct-18 3:54am

Patrice T

v4

Add a Solution

Comments

CPallini 12-Oct-18 3:16am

You should use the debugger to find out the offending code. And possibly report it here.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Patrice T · Answer 1 · 2018-10-11T18:02:00

Quote:
Segmentation fault with big array size. Why ?

Because memory is not infinite, the memory model used with your C compiler have a limit, and the OS also give a limited share of memory if you don't tell the OS that you need more.
For more details, you need to tell us :
- What is your C compiler
- Which memory model is used in your project
- The kind app generated
- Which OS

Advice: think about using some database when you have large amount of data.

k5054 · Answer 2 · 2018-10-12T03:55:00

Are you trying to dynamically adjust the size of your table variable? e.g. something like

C++

int get_int(void);    // read an int from the user - not a standard function!

int capacity;
struct person table[capacity];

// more code here ...

capacity = get_int();

for(int i = 0; i < 500; i++)
{
   // do something with table
}

If that's the case, then what you have is not going to work. When the code is compiled, the size of the table variable is fixed when it is

You need to look into dynamic allocation of memory. See malloc() and friends.

Segmentation fault with big array size. Why ?

2 solutions

Solution 1

Solution 2

Add your solution here

Preview 0