I'm given a .cpp file (for homework), this file populates an array from a file, that contains only numbers, using the standard method of populating an array but I'm supposed to modify it so that the array gets populated using a pointer, pretty simple right? Not so for me, I think I'm still confused on the concept of pointers. Here's what I have so far...
int main()
{
const int MAX_SIZE = 10;
[Code].....
My question:
-I have a file of fixed length chatracter records each 30 bytes long.
-I want to read them into an array which is 30 (or 31, say to account for the record terminator) characters by 50.
-Is there a simple (possibly elegant, even) way to do this. On my reading of the tutorials so far any method I can come up with seems a bit clunky - rather like the assembler language I used in the 1970s.
Your program will declare a 2-D array of dimensions 20 x 20. The array will be of type "character".
Functions: You will create several functions for this program.
1) One function will take the address of the array and initialize all cells to ' ' (a blank space).
If the 2-D array is odd, then you will create functions that make:
2) a triangle using '*', OR
3) a diamond using '*', OR
4) a bulls-eye using '*'. <=== this one is worth BONUS POINTS!! and is therefore optional.
If the 2-D array is even, then you will create functions that make:
5) checkerboard #1 using '*', OR
6) checkerboard #2 using '*', OR
7) a GIANT checkerboard using '*'. <=== this one is worth BONUS POINTS!! and therefore is optional.
These functions will be called from main, and return nothing. Your program will keep asking the user if they want a different kind of 2-D array and different shape. If not, then quit.
Here is what I have so far. I have only been able to get the triangle work. I have not attempted the bullseye or giant checkerboard as they are for extra credit and I can't get the main program to work.
#include <cstdlib>
#include <iostream>
void clear(char pattern[20][20]);
void triangle(char pattern[20][20], int size);
void diamond(char pattern[20][20], int size);
// void bullseye (char pattern[20][20], int size);
[code]....
I have this program for class where we just need to show that we can read, write to a text and binary file. We also need to populate an array from both a text and binary file. When the user first runs the program, the user is told that text/binary file does not work for reading because they do not exist. The user is then asked to start inpuyting integers into the console and at the same time creating and appending to a text/binary file. These values are also stored into an array as they are being inputted. Later in the program the array is run through a for loop and displayed to the screen. Displaying the array to the screen works fine here.
My problem is when the user runs the program for a second time. The text file is opened and an fgets is run to populate an array based on the numbers in the text file. That array is then used again for the user input and file writing section of the program. When the array is displayed at the end of the program the numbers do not make sense. Some appear to be correct bu most do not. When I do the similar actions to the binary file there is no problems. The text file is amended properly everytime the user runs the program. userInputText[MAXSIZE]is a char array (MAXSIZE is defined at 100000) and both textCount and textCounter are initialized to zero when the program is at this point.
Here is what the code where I believe the program resides. I have also attached the source file.
Code:
textPointer = fopen("textFile.txt", "r");
if (textPointer) {
while(fgets(userInputText, sizeof(int), textPointer) != NULL){
sscanf(userInputText, "%d", &textCount);
userInputText[textCounter] = textCount;
textCounter += 1;
}
I have two tables
Orders
ID, CreatedDate,CustomerID
1, 03/04/2014, test
OrderDetails
ID,ProductId, ProductName,Quantity,Price,Total
1, 5, Toy, 5, 1.99, 9.95
I have a gridview, im using its 'datasource dropdownlist' to populate it, i have the SQL statement
SELECT Orders.ID, OrderDetails.ProductId, OrderDetails.ProductName, OrderDetails.Quantity, OrderDetails.Price, OrderDetails.Total FROM (OrderDetails INNER JOIN Orders ON OrderDetails.ID = Orders.ID) WHERE (Orders.CustomerId = ?)
where the '?' is parameters source = QueryString, and QueryStringField= email
i have a session that is the customerEmailId, so
string CustomerEmailID = (string)Session["email"];
Response.Redirect("MyAccount.aspx?email=" + CustomerEmailID);//i have tested it and customerEmailid is test
however nothing loads in the GridView
I am trying to complete this program and as far as I am aware, the only thing not working correctly is populating the listview with my data. I've been stressing over this for a few days and achieving no success. I have to load data from two text files (incidents.txt and technicians.txt), then use a query to populate a listview with all incidents that have been closed. Also, I have to use LINQ for this assignment, so I cannot change anything that would alter my use of that. I'm thinking that perhaps the problem is with my code in form1.cs?Included are all my classes,txt files, etc.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace IncidentsByTechnician {
[Code] ....
Incidents.txt
45|1089|LEAGD10 |12|7/9/2012|7/13/2012|Problem upgrading from League Scheduler 1.0|Program fails with error 303 when trying to install upgrade.
46|1016|TEAM10 |14|7/9/2012|7/12/2012|Unable to restore data from backup|Error 405 encountered while restoring backup: File not found.
47|1034|DRAFT10 |13|7/9/2012||Can't activate product|Product activation code invalid.
48|1049|TRNY20 |11|7/9/2012||Unable to print brackets|Program doesn't recognize printer.
Technicians.txt
11|Alison Diaz
12|Jason Lee
13|Andrew Wilson
14|Gunter Wendt
15|Gina Fiori
The scenario is that I have an XSD schema; I have generated a C# class using the XSD tool in the Visual studio command line.
I have then created a basic console app, which will populate the first partial class in the generated C# class.
The program will then serialize this data and create an XML in a folder as a proof of concept.
The issue I'm having is working out the best way to populate and serialize all the data from the class, as the XSD it was generated from is quite large.
I would like to be able to randomise the data at a later stage once I have the basic populating and serializing working.
i have been fiddling with pointers but I don't understand how the proper syntax is written when I want to acces an element of an array through a pointer to a pointer...The code is all mostly just random bs for learning purposes. I marked the problem "// THIS LINE"
Code:
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#define MAX_DATA 100
int find_average(char *iden, ...) {
[Code]...
This is a sample program that declares a Matrix as a structure with an array as a pointer to a pointer. The following program is supposed to store a matrix in the structure "_Matrix" and later print the matrix just entered but it fails giving me a "segmentation fault". The sample code is given below
Code:
#include <stdio.h>
#include <stdlib.h>
struct _Matrix {
int row_size;
int col_size;
int **mat;
[Code] ......
I have the following code :
Code:
#ifndef TDYNAMICARRAY_H
#define TDYNAMICARRAY_H
namespace Massive {
template<class T>
T **AllocateDynamic2DArray(int nRows,int nCols)
[Code] .....
I wish to know how to traverse or loop through a dynamic 2D array using pointer to pointer as returned by the code above. Like I would in a static T[20][20] 2D array.
I have a program I have been working on where the user selects a date and enters the number of days to be viewed in the Calendar.cshtml view. This input renders another view (Update.cshtml) that contains two date picker boxes, one that should contain the selected date and the second one that should contain the calculated date. I am having an issue getting the date selected in the first view to populate to the first date block on the second view as the default and getting the calculated date to populate the second date block in the Update.cshtml view. In addition given the two dates, I would like to generate a calendar, which is why I chose the date picker approach and setting static dates.
Here is my code:
**CalendarController:**
using System.Web.Mvc;
using VanickCalendarApp.Models;
using System;
namespace VanickCalendarApp.Controllers {
public class CalendarController : Controller {
[Code] .....
In my refference book I have got a example with a part saying to access the a[4][0] element of the array (named a) with pointer this can be written:
*((int*)a+4)
I wonder if the cast is really required. The book says it is required so that the pointer arithmetic can be done properly. However I am not sure about it. When I work with pointers defined by myself I don't use casts similar to this one. Is there a difference between a self defined pointer and array name?
I have written this code, and at first glance it does what I want, however I am worried that
a) I am overwriting the array that is apssed from chord.getPattern()
b) Im getting a memory leak that I want to get rid of, and
c) is there generally a /what is the neater way to do it:
Code:
uint8_t* ChordBuilder::invert(uint8_t count, Chord chord) {
temp = chord.getPattern();
chord.invert(true);
//TODO count is how many times to invert. Moves root aswell however
for (uint8_t i = 0; i < count; i++){
[Code] ....
temp is a member variable of ChordBuilder - and is expressed as: Code: uint8_t* temp; I dont want the pattern that chord stores, and passes with getPattern() to change - I fear it is at the moment?
I would rather not use the "new" but I cant think how to get rid of it, however Im not sure where I would need to put the "delete"?
What is the correct method of declaring pointer to multidimensional array
Code:
int array[3][4];
int *p = array;
The above code works but it shows warning. Is it an invalid way of using the pointer? the array is an address then why am i getting warning?
I have the following situation:
Code:
void myFun(float *pfMyPtr) {
float Val[] = {0.234, 0,432, 0.322, 0762, 0.984};
pfMyPtr = Val;
}
int main() {
float *pfPtr;
pfPtr = (float*) calloc (5,sizeof(float));
myFun(pfPtr);
}
I would like pfPtr to contain the values of array Val. What am I missing here?
int * ptr = new int[5];
p += 2; //p now stores address of 3rd element in array
delete [] p;
what will be deleted??? all 5 elements or just 3rd, 4th and 5th elements of array(in result making a memory leak)
Why would you ever assign a pointer to an existing array?Take this link for example. URL....I understand that pointers use dynamic memory allocation so they are much more flexible then a built in array, but if you already have an existing array, don't you already have static memory allocation for that array? Why bother assigning a pointer? Regardless of the pointer, doesn't the program still allocate static memory to the array anyway?
View 3 Replies View RelatedI like to use a Pointer to char array. And then I would like to do a Pointer Arithmetic by incrementing the Pointer. Finally I would like to see the Addresses of the Pointer to each of the char Array Elements. I had created a program below, but I am not getting any Addresses from my Pointer.
#include <iostream>
using namespace std;
int main () {
int ArraySize;
char ch[]= "This is a Char Pointer";
char* iPtr = ch;
[Code] ....
I'm just trying to get a handle on the uses of pointers here. Though clearly from my errors I'm missing a key concept. Here is my code: (You can assume that the array, "array_size" has values in it, I did this part in another function)
int main() {
bool **ptr_array;
int num;
int *array_size;
cin>>num;
[Code] ....
Once the program reaches the word[num] = false; some unhandled exceptions pop up.
I simplified my code a bit from my actual program and mixed up the loops, now the code should be in its correct form.
How would I go about having a pointer to an array element specificity a character in a c-string.Every thing I try will not even build.An array is already a pointer to the first location of the array right?
char *pHead;
char *pTail;
pHead = sentence[0]; <=== This wont build
pHead = &sentence[0];
pHead = sentence[0]*;
*pHead = sentence[0]; <===== this builds but is not storing anything
int sum(int (*ar2)[4], int size);
// I dont know what the ar2 is going on
int main(){
int data[3][4] = {{1,2,3,4},{5,6,7,8},{9,10,11,12}};
int total = sum(data, 3)
return 0;
}
I was struggling the last 2 days with this C script supposing to open a list of strings (input as fopen(argv[1])and allowing to access to any element of the list. I created an array *gcm[10000] and a pointer *(*gcm_ptr[10000] = &gcm. However, when I try to list whatever n[i], it always gives me the last entry.
View 4 Replies View RelatedAlright, so I have a code that's not giving me errors, but it doesn't seem to retain what I put into an array. Not sure If I'm missing something...
Code:
#include <stdio.h>
int main (void)
{
const char *pointer;
const char alphabet[] = "ABCDEFG";
pointer = &alphabet[5];
printf("pointing to %c of the alphabet
", pointer);
return 0;
}
Trying to get my pointer to return the letter in the [5] spot or "F". Not receiving any errors when compiling, but I seem to get different answers every time I run it.
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.
I am using pointer to display values of an array but its output is not correct example 23424,0, -323423 etc... whats the problem with my code:
Code:
#include<stdio.h>
#include<conio.h>
int main() {
clrscr();
int arr[10][10],rows,cols;
int* ptr;
[Code] ....
first code,
Code:
int aRRay[] = {2,4,8,-2,-1,100};
int *ptr;
int loop;
ptr = &aRRay[0];
}
[code].....
first code result, " aRRay[] " and " ptr + loop " are in the same result
second code result, " aRRay[] " and "ptr + loop " are in the same result too,
third code result, " aRRay[] " and "ptr + loop " are in the same result Except "aRRay[4] = -1 with ptr + 4 = 100 " and "aRRay[5] = 100 with ptr + 5 = 14"
Question:Why the third code had a different result ? Its only because of the increment ++ptr or the round brackets on the *(++ptr) ?