C/C++ :: Array Of Structs - Reallocate Distorting Data Records
Mar 29, 2014
I have an array of structs (PlanetRecord). Each time I realloc, one of the records gets distorted. Here's my memory allocation code:
if(currentArraySize == 0) {
printf("allocating memory
");
planetRecords =
( PlanetRecord* ) malloc( sizeof( PlanetRecord ) * BLOCK );
currentArraySize = BLOCK;
[Code] ....
I am increasing my array in multiples of 5 (or in this case, my constant BLOCK). This is the result of my printout (t1-t40 is correct, the rest of the values should be 1):
t1 1 1
t2 1 1
t3 1 31329
t4 31297 1
t5 1 31249
t6 31217 1
and so on .....
I noticed that in my test, realloc was called 7 times. My array has 7 distorted records. Each time I call realloc, it is distorting one of my records.
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Jul 15, 2013
Code:
void readFile(struct course *d, char* filename){
FILE* fp;
char buffer[100];
int i = 0, array_size = 100;
struct course *temp;
[code]....
I will be using this to read data from a file. I start with an array of 100 structures being passed to the readfile function. Once it reads 100 lines (i == array_size), I want to double the array size until I have finished reading the file.
Two questions.
1)My initial thought was that I needed to keep track of the lines read with my variable, i. However, is there a better way?
2)My program is crashing right now at the call to double_array_size function. What is wrong with my code? Never dealt with dynamically allocated array of structures and functions.
I read online that I should change my code in the following manner.
Code:
void readFile(struct course *d, char* filename) {
FILE* fp;
char buffer[100];
int i = 0, array_size = 100;
struct course *temp;
[code]....
I can paste the "error messages" if you like, but it is a page full of stuff I have never seen. glibc detected, Backtrace, Memory Map, and a bunch of numbers and hexadecimal stuff like addresses.
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Apr 15, 2013
I am having a lot of trouble being able to get data from a file and input it into given structs and arrays of structs and then outputting the file. We are given a file that contains 96 lines and looks like this:
Arzin, Neil
2.3 6.0 5.0 6.7 7.8 5.6 8.9 7.6
Babbage, Charles
2.3 5.6 6.5 7.6 8.7 7.8 5.4 4.5
This file continues for 24 different people and then repeats with different scores (the second line).
The first number, in this case is 2.3 for both people is a difficulty rating. The next 6 numbers are scores.
We are given this data in order to set up our structs and arrays and my code:
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <cmath>
using namespace std;
int main () {
ifstream inFile;
inFile.open("C://diveData.txt);
[Code] .....
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Mar 10, 2015
That;s what i have so far: problem: the output data is not correct.
input file
1301 105515018 "Boatswain" "Michael R." CSE 230 ="R01"
1301 103993269 "Castille" "Michael Jr" CSE 230 ="R03"
1301 103993267 "Castille" "Janice" CSE 230 ="R03"
[Code]....
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Sep 8, 2013
nestedTriangles.cpp description:
The program takes as input a pair of triangles, specified be giving the coordinates of each trangle's vertices. It then determines if either triangle is "nested" within the other, meaning that one triangle lies entirely within the interior of the other.
Pseudocode:
One triangle lies within another if and only if all three vertices of the first triangle lie within the interior of the second triangle.
Suppose that we have a triangle with vertices A, B, and C, described by the coordinates (xA, yA), (xB, yB), and (xC, yC), respectively. The sides of the triangle are the line segments AB, BC, and CA.
A line passing through two points (x1, y1) and (x2, y2) can be considered to be the set of points (x,y) satisfying the equation
f(x,y) = 0
where f(x,y) is given as
f(x,y) = (x - x1) (y2 - y1) - (y - y1) (x2 - x1)
One of the interesting things about that f(x,y) is that we can use it to determine which "side" of the line an abitrary point (x,y) is on:
If f(x,y) = 0, the point is exactly on the line. All points for which f(x,y) > 0 are on one side of the line, and All points for which f(x,y) < 0 are on the other side So the problem of determining whether a point (x,y) is on the inside of a trangle can be checking the sign of f(x,y) for each of the three lines making up the triangle. A complicating factor is that we don't know, for any given triangle, whether those three signs should be all positive, all negative, or some mixture of the two.
The centroid of a triangle can be computed as the "average" of the x and y coordinates of the vertices:
xcen = (xA + xB + xC)/3
ycen = (yA + yB + yC)/3
This point (xcen, ycen) is definitely inside the trangle (unless the triangle is "degenerate" and has no interior points). The problem of determining whether (x,y) is on the inside of a triangle can therefore be resolved by checking to see if it is on the same side of each of the trangle's line segments as (xcen, ycen).
What I need:
I want to fill in the missing bodies for the functions eval and areOnSameSideOf, which manipulate line segments. I think calling eval from within areOnSameSideOf will simplify the implementation of the latter.
Code:
#include <iostream>
using namespace std;
/**
* 2D Cartesian coordinates
*/
[Code]....
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Sep 8, 2013
nestedTriangles.cpp description:
The program takes as input a pair of triangles, specified be giving the coordinates of each trangle's vertices. It then determines if either triangle is "nested" within the other, meaning that one triangle lies entirely within the interior of the other.
Pseudocode:
One triangle lies within another if and only if all three vertices of the first triangle lie within the interior of the second triangle.Suppose that we have a triangle with vertices A, B, and C, described by the coordinates (xA, yA), (xB, yB), and (xC, yC), respectively. The sides of the triangle are the line segments AB, BC, and CA.A line passing through two points (x1, y1) and (x2, y2) can be considered to be the set of points (x,y) satisfying the equation
f(x,y) = 0
where f(x,y) is given as
f(x,y) = (x - x1) (y2 - y1) - (y - y1) (x2 - x1)
One of the interesting things about that f(x,y) is that we can use it to determine which "side" of the line an abitrary point (x,y) is on:
If f(x,y) = 0, the point is exactly on the line.
All points for which f(x,y) > 0 are on one side of the line, and All points for which f(x,y) < 0 are on the other side So the problem of determining whether a point (x,y) is on the inside of a trangle can be checking the sign of f(x,y) for each of the three lines making up the triangle.
A complicating factor is that we don't know, for any given triangle, whether those three signs should be all positive, all negative, or some mixture of the two.
The centroid of a triangle can be computed as the "average" of the x and y coordinates of the vertices:
xcen = (xA + xB + xC)/3
ycen = (yA + yB + yC)/3
This point (xcen, ycen) is definitely inside the trangle (unless the triangle is "degenerate" and has no interior points).
The problem of determining whether (x,y) is on the inside of a triangle can therefore be resolved by checking to see if it is on the same side of each of the trangle's line segments as (xcen, ycen).
I want to fill in the missing bodies for the functions eval and areOnSameSideOf, which manipulate line segments. I think calling eval from within areOnSameSideOf will simplify the implementation of the latter.
Code:
#include <iostream>
using namespace std;
/**
* 2D Cartesian coordinates
*/
struct Point {
double x;
double y;
[code]...
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Apr 1, 2013
I can't seem to remember everything I should about constructors. I'm looking for a way to create an array of structs, using a constructor. My code should explain.
struct myStruct
{
private:
int structInt1, structInt2;
[Code].....
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Feb 14, 2013
I have an assignment where I need to use pointers to do a few things and I am a little confused on the syntax of it all. My question is how do you use a pointer to point to an array of structs.
For example
struct info{
char firstName[15];
char lastName[15];
};
main() {
info person[4];
cout << "The third letter of the second persons first name is: "; // ?????
}
how would I define a pointer to point to the third letter of first name the second person in the "person" array.
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Mar 31, 2013
I am versed in qsorting struct members within a struct instance, as in the example below:
Code:
#include <iostream>
#include <stdlib.h>
using namespace std;
struct item_database {
[Code]....
What I CANT do however is to sort an array of structs by one of its members. This is a complete different problem even if it sounds similar.
In other words, the problem is this; Say we have a struct:
Code:
struct item_database {
int key;
string token;
};
Then we declare an array of this struct in the heap:
Code: item_database *idptr = new item_database[700000]; and initialize its values.
How would one go about sorting this heap array of structs by its member function "token"?
I used the following call to qsort (standard library) and call to the compare function but it doesnt work:
Code:
qsort (idptr, 1000, sizeof(string), compare);
Code: int compare (const void* a, const void* b){
if (*(char*)a >= *(char*)b)
return 1;
else
return -1;
}
Or in more lamens terms say we have the following stuct instances:
Key: Token:
1 Hello
2 World
3 How
4 Are
5 You
Then I need those structs to order according to token (alphabetically, increasing or decreasing depending whats in our compare function).....
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Nov 20, 2013
what I am trying to do is to pass to a function the address of an array of structs, so I can later modify the items within the struct, within the array
Code:
typedef struct { //A struct of name auctionint bidder;float bid;} auction;
void myFunction (auction * auctionItem[]){(*aucItem[x]).bid = y;(*aucItem[x]).bidder = z;}
int main(){auction theItems[10];
myFunction(theItems);} Where x, y, and z can be any number.
When I try to run my code the IDE (I'm using Code::Blocks 12.11) does not give me any errors, but it does give me a warning:
warning: passing argument 3 of '<function name>' from incompatible pointer type [enabled by default]
and the note:
note: expected 'struct <struct name> **' but argument is of type 'struct <struct name> *'.Also, when I run the program, it will crash and return garbage.
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Mar 6, 2015
I have a structure product_array *pa that contains a pointer *arr to an array of structs and count that adds 1 when a new product is added (set to NULL initially). I have to write a function which adds a new product entry to that array. One product entry has *title, *code, stock and price parameters. The array is dynamically allocated and I’m supposed to:
1. Reallocate space for array.
2. Update product_array.
3. Initialize it.
Also, code should be truncated to 7 characters.Products can be added multiple times, so the initial size is unknown.
Code:
void add_product(struct product_array *pa, const char *title, const char *code, int stock, double price)
{
for (int i = 0 ;; i++){
pa->arr = realloc(pa->arr, sizeof(struct product_array));
[code]....
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Dec 18, 2013
How do I set all of these string and double value(s) to 0?
Code:
#define MAXcharacters 12
#define MAXaccounts 100
struct Records {
char userid[MAXcharacters + 1];
char password[MAXcharacters + 1];
double balance;
};
[code]...
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Mar 18, 2015
I need to scan a .csv file that contains the following info:
programming,03,60,141,01,W,2015
programming,03,60,141,30,W,2015
Algebra,03,62,102,02,S,2013
Religion,08,98,938,20,F,2014
So i made a struct:
typedef struct CourseInfo {
int courseID;
char courseName[50];
char courseCode[13];
char term[7];
} courseinfo;
Where course code is the 4 numbers after the name together and the term is the letter and year in the last two pieces of info. I got this to work:
int main() {
FILE *p;
p = fopen("input.csv", "r+");
if(p == NULL) {
puts("The file could not be opened");
[Code] ......
But lets say i dont know how many lines i have in my file and i want to count them and then use that size for my array so i tried this by:
int main() {
FILE *p;
int lines = 1;
char ch;
p = fopen("input.csv", "r+");
if(p == NULL) {
[Code] .....
But the second program is not working for unknown reasons. I do not get any errors but its not scanning the info because when i print the info later on it prints out random symbols.
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Feb 24, 2013
Background: I'm writing a convolutional encoder (and decoder, eventually) for a microprocessor (PIC24), for which I'm using structs and pointers to move from state to state. So far as I'm aware, everything I'm using in the PIC involves nothing other than ANSI C.
I have a little experience with structures, having written a linked-list program for a class a couple years back, but nothing since and never used structure arrays. I have the feeling I'm missing something basic here, which is what's so frustrating. The most confusing error (and I suspect the root of most of them) is the 'state undeclared', which I just can't figure.
The errors I'm getting are:
encoder.c:11: warning: 'struct memstate' declared inside parameter list
encoder.c:11: warning: its scope is only this definition or declaration, which is probably not what you want
encoder.c: In function 'state_init':
encoder.c:22: error: two or more data types in declaration specifiers
encoder.c:25: error: 'state' undeclared (first use in this function)
encoder.c:25: error: (Each undeclared identifier is reported only once
[Code]....
Code:
Code: //Includes
#include <stdlib.h>
//------------------------------------------------------------------------------
//Creates state machine and passes back pointer to 00 state
void state_init(struct memstate* startpoint)
{
extern struct memstate
{
char output0; //output if next input is 0
[code]...
NB: I'm aware that at the moment, this code will do nothing except spin round that do-while loop. Once it's actually compiling I'll drop in some simple button-based test code so it'll check for the correct output.
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Sep 20, 2013
I want to write a program to record my neighborhoods's name and address by using an array of structs and file.
my array of structs is
Code:
#define SIZE 30
typedef struct{
char name[30];
char address[100];
}Detail;
Detail neighbor[SIZE];
And I want to make adding,deleting, and searching functions.Something like
Code:
void add();//Add name and address to a file,
//and add more to the same file if I want to.
void del();//Delete or Change some neighbor's name or address
//in the same file(Can I?)
void search();//Search name and show detail
So I started to code adding function first, but I don't know that I need to use pointer to code each functions relations, and I don't know how to check that my input's already exists yet. But I started some code below...
Code:
void add() {
int i=0;
FILE *fp = fopen("neighborhood.txt", "at");
if ( fp != NULL ) {
do{
[Code]......
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Mar 10, 2015
I'm trying to read the data from a file i/o and put them into an array of structs. But when I run the program, it gives me a bunch of "garbage" as an output. my code and see
#include<stdio.h>
#include <stdlib.h>
#include<string.h>
[Code].....
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Mar 28, 2015
#include <iostream>
#include <fstream>
using namespace std;
int main() {
int r = 0;
int c = 0;
int num[17][15] = { 0 };
[Code] ...
// Here is my code for displaying the data from the text file into a 2d array and height next to it, but I am not able to diaplay the height from 60 to 76 next to the row of the 2d array, as shown in the table below. This is my program:
Recently the health authorities have listed a new way to calculate the body mass index (BMI) of an individual.
Values of 20 – 24 are classified as normal, 25-29 as overweight, and 30-34 as heavy.
The table below is a portion of a typical BMI table.
BMI:202122232425262728293031323334
Height:
60102108113118123128133138143149154159164169174
61106111116122127132138143148153159164169175180
.
.
.
MY task is to write a program that does the following things:
1.Produce the table by reading in the data from bmi.txt (on Moodle) into a 2-D array.
2. Display the table neatly on the screen, with row and column headings. The BMI should go from 20 to 34. The height should go from 60 to 76 inches.
3. Prompt the use for their height (in inches) and their weight.
4. Make the program print the closest BMI.
If their weight is lower than the values on the table, use 20 as the BMI.
If their weight is higher than the values on the table, use 34 as the BMI.
5.Loop the program so the user can find more BMI’s.
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Sep 25, 2014
I have the records "File attached"
My query is
from c in JOB_HISTORies join d in DEPARTMENTs on c.DEPARTMENT_ID equals d.DEPARTMENT_ID select new {d.DEPARTMENT_NAME,c.START_DATE,c.END_DATE}
How do i put the record Accounting in the same row to avoid duplication.
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Jan 28, 2014
Is there a way to indicate how many records exist in a given file? For example, vectors have the vector.size() command to show the number of given elements. Is there a such command for files and records?
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May 8, 2014
Is this the right codes for deleting a recoed on the text file.
void dlte(){
string line, recorddate;
cout << "Please Enter the date of record you want to delete: ";
cin >> recorddate;
ifstream myfile;
ofstream temp;
myfile.open("herald.txt");
[Code] .....
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Nov 19, 2014
I have to ask the user if they want to delete any records. The user can enter -1 to finish deleting records. I have to write the remaining records in an output file. So, i have this, but
1) it doesn't let me enter more than 1 id, and
2) it doesn't output anything to my output.txt.
records.txt
6
123 Jose Garcia 99
345 Luis Garcia 87
234 Jazlyn Soriano 79
456 Carter Sander 95
567 Natalia Soto 67
789 Isabel Santana 80
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
using namespace std;
class Student {
private:
int id;
[Code] ....
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Nov 3, 2013
How do i go about updating a specific record in sequential File using a primary key in c++. I used Inventory number as my primary key..
Code: int locate[2];
string fname, lname, add, name, address;
int num, foundit;
Customer customer;
[Code].....
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Aug 6, 2014
I've got a program to read the input file as records. The problem is all it does is cout Record Number etc but it doesn't grab the data.
#include <fstream>
#include <string>
#include <iostream>
using namespace std;
int main() {
const int RANGE = 12;
string tab[RANGE];
[Code] .....
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Feb 17, 2015
I've implemented a records system for a college assignment and everything works as intended. However upon increasing the amount of records to store in my array above 10, the program crashes upon adding a new employee and I can't work out why...
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#define esize 10 /* Change max-records */
[Code] .....
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May 16, 2014
what I need to do is load a dataset with the most recent record for each item in the database table. Each item has an ID, location ID and date along with some numeric data. the item ID, location ID, and date is referenced in each record of the table. So each item will have multiple records with different dates that could be anything. To make things worse there may be the same item in multiple locations. and each locations items most recent record needs to loaded in to the dateset and then displayed in a data grid. At a later time there will be a location sort as well so only items in a particular location or group of locations will be loaded. More question on the data grid to come.
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Jan 27, 2014
This is my code as following
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
[Code]....
I have driver table this is my fields as following
DriverID INT
DriverName nvarchar50
Nationality nvarchar50
Address nvarchar50
I have form driver have 4 texbox
textbox1 DriverID
textbox2 DriverName
textbox3 Nationality
textbox4 address
this table have two records
when i press buton next (NextBtn_Click)to go third record it not accept I need next button increase by 1 if record not exist and update this in table How i do this example if i have two records
1 aln american newyork
2 adam british british
when i press next button it ok work in records exist but when i press next button to third record it not accept why what i need is when press next after 2 it come 3 in text box driver id and update this number in table
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