C :: Segmentation Fault When Dynamically Allocating 2D Array
Apr 20, 2013
This is a homework assignment where I have to read a file into a dynamically allocated 2d array. The file format is
10
Jim 3.6
Jake 4.0
Will 3.0
Sara 3.4
Mike 2.5
Ellen 2.9
Melissa 3.9
Eric 3.8
John 3.5
Beth 3.9
where 10 is the number of students followed by the students and the gpa's. There is more to the program but I have not implemented it yet because I am getting a segmentation fault. The output I am getting when I print the array is
Jim 3.6
Jake 4.0
Will 3.0
Sara 3.4
Segmentation fault
I can see where the problem lies. If I raise value for row when I am allocating the rows of the array, all of the names print. I just do not see why I need to. From my understanding the row * sizeof(char*) should give me enough room for 10 entrie.
Code:
#include <stdio.h>
#include <stdlib.h>
void sort();
int main()
[Code] .....
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Nov 24, 2013
Working on this one from the Jumping into c++ book. The book asks that I create a multidimensional array at run time based on user input and fill it with a multiplication table
My code compiles fine but throws an uninitiated error for p when I try and run it.
Code:
void multiDimentionalMultiplication(int x, int y, int z){
int ***p;
**p = new int[x];
std::cout << "Allocating array.
[code]....
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Jun 14, 2013
I am trying to figure out the syntax to dynamically allocate a single dimension of a triple dimensional array. Basically i have a 2D array of structs. but each struct is an array (basically rows of the information). The rows of this structure need to be allocated dynamically, but the height and width of the overarching structure are static.
Basically: Struct * ts_FieldInfo[100][100] = new Struct[Class.returndataitems()];
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Apr 15, 2014
so I have this code that dynamically allocates a pointer array increasing and removing elements of the array as its operated on.then it sorts and prints out the array when the user is finished operation on the array. i get this error message when running the program though.
"Unhandled exception at 0x0F474F98 (msvcr110d.dll) in Lab10_VarArray.exe: 0xC0000005: Access violation reading location 0xCCCCCCC0."
this is my code
#include <iostream>
#include <cstdlib>
#include "Header.h"
using std::cout; using std::endl; using std::cin;
int main(void) {
char op='x';
[Code]...
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Apr 18, 2015
I'm trying to dynamically allocate a standard array at runtime in the function of a class where the array is "owned" by the calling class. The calling class knows nothing about the array before it makes the call to create the array other than the datatype of the array. But the full array of data needs to be returned.
It appears that the pointer being passed makes a copy of the pointer on the stack and then when the function returns it pops it off the stack and the array is a memory leak because the pointer is once again a nullptr as it was before being passed and the array has not been deallocated with delete yet (as it should not have been).
(Edit:Unexpected value of MyArray being a nullptr instead of pointing to an array after returning from line 09.)
class Class1 {
void FunctionA() {
Class2 OwnedClass;
int* MyArray = nullptr;
int SizeOfMyArray = 0;
[Code] ....
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Jan 18, 2014
I'm trying extremely hard to understand pointers and I have the basic concept down.. I feel as though my knowledge of dynamically allocated pointers and pointers in general is not enough to understand the logic behind what I'm trying to do. The problem is that the donations array must be able to accept any number of donations. I've made it do just that, but there is also an array of pointers which must each point to the same element in the donations array. The program works if I assign int *arrPtr[100] for example, but it does not work if I try to dynamically allocate it to accept the same number of elements for donations entered by the user. Here it's the snippet
#include <iostream>
using namespace std;
//Function Prototypes
[Code]....
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Aug 27, 2014
Write a program that reads in the names and the ages of ten people. Store these data in two arrays (make sure that the entered names are not longer than the array size you choose). Then produce a table of ten lines, with each line giving the name and age of a person along with the (positive or negative) deviation of that person's age from the average age. The code I wrote to fill in the arrays looks as follows
Code:
#include<stdlib.h>
#include<stdio.h>
int main()
{ // begin main()
// array length
[Code]....
When I compile it, it gives me warnings that few of the variables I declared aren't used, but that is not affecting the program at all. When I run the program, it allows me to pass the names and ages into the arrays, but when it comes to displaying them, I'm getting a 'Segmentation fault'. I used very similar code in Java to write the program, and it worked fine so what is the problem with C then?
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Jun 4, 2013
i want to enter a URL in as a string, and extract just the URL part.
eg: Code: input: URL....
output: URL....
Input: URL....
output: URL....
part of our header file which we cannot edit (the url is always less than 140 characters):
Code:
char url[140];
function i am having problems with
Code: void init_url(char new_url[])
{
/*
This function sets the variable url to new_url and url_size to the number of characters in the url
It also initializes url_error_flag
}
[code]....
whenever i try a URL like the second one above with no '?' i'm getting a segmentation fault error which is becase i'm trying to access an invalid index. i'm not sure what an array is initialized to when i do not explicitly assign it anything, for example
Code:
char values[140] = {0};
i've read it depends on whether it is a global vs local array or something? i know this could all be fixed with simply assigning the array values to 0 but i'm not allowed to edit the header file.
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Jan 25, 2013
This function should replace all instances of a character in a given character array, while returning the amount of characters changed, but I keep getting a segmentation fault at the highlighted area.
I'm only supposed to use pointers so arrays are out of the question, and I don't think we are allowed to use the string.h library as well. How I could avoid something the segmentation fault or ways to fix it?
Code:
int replaceChars(char replace, char find, char *input) { int i, j;
//Finds length
for(i = 0; *(input + (i + 1)) != ' '; i++);
int c = 0;
for(j = 0; j <= i; j++) {
if(*(input + j) == find) {
*(input + j) = replace; //Segmentation fault happens here
c++;
} }
return c;
}
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Sep 3, 2013
When I try to run the code, I get a segmentation fault core dumped, it returns 139 (0x8B)
The file it is pulling from is a list of numbers, but without the string, the output ends up going from values of ~70,000 to values around 50
#include <iostream>
#include <fstream>
#include <cstdio>
#include <cstdlib>
#define MAX 29656
using namespace std;
string el[MAX];
ifstream file1("results.txt");
ofstream file2("Energy1.txt");
[Code] ....
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Sep 18, 2013
I have created a database for music cds:
Code:
#include<stdio.h>
#include<stdlib.h>
#define array
typedef struct cd_database
[Code]....
When I am using malloc instead of arrays the code is not working properly after exit. I have tried alot but can't came up with a way
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Nov 5, 2013
I have an abstract based class and three derived classes. I also have a templated hash table class(using chaining as my collision resolution method, an array of stl lists), and a class to parse commands from a file, this also holds the instantiation of the hash table. My question is that since my command parsing class's constructor instantiates the hash table in the main driver(unable to modify) how can I make this dynamically allocated using data from the file?
template<class T>
class hashTable{
public:
hashTable(int size);
~hashTable();
[Code] .....
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Jan 23, 2013
I am working on a distributed application in C. My program gives segmentation fault and aborts execution. But, when I try to run it through gdb, it keeps on running although without giving a useful output. I realize that I do not put much information in my query. But, what general causes could generate this behaviour. I am interested to find the cause of segmentation fault.
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Jul 21, 2013
I can't understand why my program keeps on getting "Segmentation Fault". The last time I checked (in UBUNTU) it was already working, now I'm testing it in Windows and I keep on getting "Segmentation Fault".
Code:
#include <stdio.h>
#include <string.h>
int main(){
char string[1500];
char word[100];
}
[code]....
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Oct 28, 2013
Writing a program to search a file and print out the occurrences of each letter in the alphabet.
Code:
#include <stdio.h>
char input[500];
int input_c[26];
int i;
char count=0;
}
[code]....
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Jan 16, 2015
I am using scientific linux. In the directory user/project/Build, after I ran 'make' to compile and link all the cpp files,I had no problems. But then, when I went to directory user/run/run.sh, which runs the project binary in user/project/Build/bin/project, I get a segmentation fault error. In the directory user/run, I enter 'gdb' in the command prompt and get the message "*** No targets specified and no makefile found. Stop." What am I supposed to do to detect the segmentation fault?
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Jun 28, 2013
I can't work out why I get a Segmentation Fault with my C++ program.
Here is the code:
#include <iostream>
#include <string>
#include <stdexcept>
[Code].....
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Dec 7, 2014
GameMaster.h
#includes ...
class GameMaster
{
[Code].....
I get the segmentation fault whenever it tries to insert the first player.. however whenever i do this :
void MakeSquad(char type, string name, int coordX, int coordY, char dir, int squad)
{
GameSpace::MapSquadType MapOfSquads;
MapOfSquads.insert(make_pair(name , Squad(squad)); // Squad( int ) just converts the int squad number to the Enum.
}
I do not get any errors or segmentation faults..
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Feb 25, 2012
Code:
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#define FILEPATH "./input.txt"
#define FILEPATH2 "./copy.txt"
[Code] ....
The problem is probably the fact that I'm using the variable s in the wrong way, but as I'm very bad at C and C++, at least so far anyway, I've no clue what's wrong. Is it my size that I passed in the marked method?
Also, how do I tell it, later, once this starts to work, to pass the file name of the file it'll copy to as the first param and the file it reads from to the pipe as the second param?
I'm supposed to be reading from a file, and as I was given some code, but it's probably in C and not C++, even if it is, I'm still not that great at C++ either, but anyway, I'm to have the program read from the file and write to the pipe and have the child read from the pipe and write to the output file.
FileCopy copy.txt input.txt
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May 3, 2013
The point of this code is to get 15 names and then hash them. After one name is entered I get a segmentation Fault and the program crashes.
Code:
//driver file
#include <iostream>
#include <vector>
#include <string>
using namespace std;
[Code] ....
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May 29, 2013
I have this piece of code that causes segmentation fault:
Code: .... check argv[2] exists ....
std::string* op_file;
...
std::cout << "argv[2] is: " << argv[2] << std::endl;
op_file = new std::string(argv[2]);
...
The result I am getting is:
Code: argv[2] is: somefile.txt
Segmentation fault (core dumped)
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Apr 26, 2013
I have written a small program for a class to convert decimal to binary and the program itself works, however, I am storing the binary bits in a stack that is in a header file (which I have used successfully before). It appears to push the bits to the stack just fine, however, when I use the printStack function I get a segmentation fault.
Here is the stack.h header file:
Code:
#include <stdlib.h>
#include <stdio.h>
struct stackNode {
int data;
struct stackNode *nextPtr;
[Code].....
And here is the main program that does the conversion:
Code:
#include <stdio.h>
#include "stack.h"
int binary (int x);
int main() {
int choice = 0;
printf("
[Code].....
One other thing of note, whenever I try to modify the printStack function, that function then seems to not work at all.
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Jul 7, 2014
Code:
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
/* h(a)=abcab,h(b)=acabcb,h(c)=acbcacb */
void h_i(int i, char *w, char *a, char *b, char *c)
[Code] .....
Above program increases string like this example.
Let say h(0)=01 and h(1)=10 and let say our first string is w=0 h(w)=01, h^2(w)=0110 h^3(w)=01101001..etc.
We have used h map, which is given in the program comment statement. Same thing, program is doing for three letters. These three letters we have passed as argument in h_i function. e.g. h_i(2,w,"a","d","g") function will apply the 3 letter map h(definition is given in commented form in program) 2 times on string w.
In program w=a; and three letters are a, d and g. /* h(a)=abcab,h(b)=acabcb,h(c)=acbcacb */ here b=d and c=g.
Above program gives core dump at free(w2) free(w1). if we remove these free statements then it gives correct answer. But, we want to free w1 and w2 in the above code. How can we make free both w1 and w2 strings?
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Apr 15, 2013
I want to know what was wrong with my code when I submitted. It's a Traveling Salesperson Problem, and the code is complete for the most part. I just can't seem to find what's causing the segmentation fault even after attempting to debug with gdb. Something is supposed to be wrong with line 76, but I don't see how my arrays are messing up. I've looked through this code countless times, and I know I'm just missing something small. I just don't want to end up making whatever mistake I made on this again in the future.
Code:
#include <stdio.h>
#include <stdlib.h>
#define SIZE 20
[Code]....
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Feb 18, 2013
I am having trouble running the following code. I am getting a message segmentation fault (core dumped)
Code:
#include<stdio.h>
#include<ctype.h>
#include<time.h>
main() {
int iuser;
int irand;
srand(time(NULL));
[Code] .....
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Nov 6, 2013
Despite seeing the correct data in gdb when I
Code:
p *(DownloadFileChunkResponse.DownloadFileChunkResult)->__ptr@100
The following C code gives me a SEG FAULT
Code:
calloc(NewMediaChunk, ChunkSize);
memcpy((void *)NewMediaChunk,
*(DownloadFileChunkResponse.DownloadFileChunkResult)->__ptr, ChunkSize);
How I got this wrong. BTW The data I am attempting to memcpy is the frontend of an MP4 file containing a number of NULLS.
Code: 00 00 00 30ftypmp42 00 00 00 00mp42mp41 00 00 dfree
BTW ChunkSize is 64000
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