I would like to create a table but I dont know how big. Thats why I want to use variable to describe its size. Something like that:
int x = 5; //I will use a function to set x
int Table[x];
What should I do to make it work?
This problem is best explained by looking at its output below. I stored 15 different values but when retrieved some are wrong.
#include <iostream>
using namespace std;
class A {
public:
int ** pointer;
[Code] ....
I need to store and retrieve the 15 different values correctly. How to solve this? The main thing is, I need to store the pointer in class A objects.
Here is an example,
Code:
class A {
public:
virtual void foo(){}
virtual void foo2(){}
virtual void foo3(){}
};
int main() {
A a;
int ret = sizeof(A);
return 0;
}
Basically object a contains a virtual table pointer which is of size 4 bytes. Since class A should have a virtual table which contains three pointers pointing to foo, foo2,foo3 separately. So the virtual table should be of size 12 bytes. I wonder where is virtual table located in memory?
How to approach this? Not very clear on how hashing works..
Insert the following numbers into a hash table of size 10 (ie an array with 0…9 index position) using a hash function h(k)=(k*71+94)%10 and using Linear Probing.
75, 98, 43,1,-56,93,101,34,23
Insert the following numbers into a hash table of size 10 (ie an array with 0…9 index position) using a hash function h(k)=(k*71+94)%10 and using Chaining.
75, 98, 43,1,-56,93,101,34,23
im doing a program to store name, age, time and fitness. and i need to hold a table of 5 such records.can i do this?
#include <iostream>
using namespace std;
int name1, age1, time1, fitness1;
int name2, age2, time2, fitness2;
int name3, age3, time3, fitness3;
int name4, age4, time4, fitness4;
int name5, age5, time5, fitness5;
[code].....
I'm trying to write a program which prints a table of ASCII chars, I'm not really done with my thoughts on it but I already
ran into the following error:
Error: cannot initialize a variable of type 'char' with an rvalue of type 'char (*)[16]'
Here's my code so far:
# include <iostream>
using namespace std;
int main() {
char asciiTable = new char[8][16];
int nextSign = 0;
[Code] .....
I have an application in C sharp that searches for a record in a sql database using a datetimepicker,the output is displayed in a datagridview.When I execute it I got a blank datagridview with empty columns.I can not view the content and I don't get any error message.
Here is my code:
DataTable dt=new dataTable();
SqlDataAdapter sda=new sqldataadapter("select * from Delivery where convert
(char(20),Delivery_Date,112)='"+ dateTimePicker1.value.Date,con);
//con is sqlconnection
Sda.Fill(dt);
Datagridview1.DataSource=dt;
I am having trouble getting the cout statements that I commented out to work properly. And I can't figure out why the first movie in the movies.txt file displays at the end of the list in my output screen when it should only display once as the first item. I am also having trouble figuring out where and how to set up the static variable.
Purpose : This assignment requires that you to develop a program using the classes listed above. Specifically you will build a hash table containing movie data. The collision strategy will be to build linked lists as the array elements.
Program Specifications : Your program will read the data from the file named Movies.txt located in the StudentFiles1.zip file on the Connections Portal. Each record contains 2 fields separated by a space. They are:
FieldsData Type
Motion Picture Association Code (MPAC)Integer
Movie NameString
Your application program will read each record, create a Movie structure instance and place that structure instance into the hash table.
You will need to modify the appropriate code to provide for an audit trail of the hash table construction. To accomplish this, you will use cout statements in the above class member functions. You will need to modify them to include couts, but the modifications will be relatively small. If not, you are doing it wrong. The hashing algorithm to use is:
Index = int ( 0.618033 * MPAC) % size
Make the array size a constant and set it to 10.
Include a counter for the number of collisions that occurred in building the hash table. Including a static variable in the LinkedList or List class is the best method for doing that.
See the sample audit trail below for the first 5 records on Movies.txt and the size of the hash table set to 3. This is shown for illustration only. The full file will have different locations calculated.
1101-Casablanca is being added
The hashed location is 2
There was no collision loading 1101-Casablanca
------------------------------------------------
1200-Duck Soup is being added
The hashed location is 0
There was no collision loading 1200-Duck Soup
------------------------------------------------
[Code] ....
After the above is displayed, prompt the user to enter the MPAC of a movie to locate. Produce an audit trail when locating the requested movie as shown below: Make sure you list all movies that have collided at the hashed location. That may also cause you to modify one of the existing ADTs a little.
Will search for 6601
at the hashed location is 2
There was a collision here with 6601-Wizard of Oz
There was a collision here with 1101-Casablanca
retrieved from hash table: 6601-Wizard of Oz
[Code] ....
How do I insert a array size as variable?
View 5 Replies View RelatedThe WinAPI has a struct like this for raw input:
Code:
typedef struct tagRAWINPUT { RAWINPUTHEADER header;
union {
RAWMOUSE mouse;
RAWKEYBOARD keyboard;
RAWHID hid;
} data;
[code]...
The definition of the struct doesn't show it but the documentation says that bRawData is variable length. sizeof(RAWINPUT) will not be the correct size when the data field is of RAWHID type so how do you allocate a variable with automatic storage type that has the right size for the entire struct? You can get a header that has the size for the entire struct but how do you actually allocate storage space for the data without using malloc? I've seen some example code that used a char array but that violates aliasing rules and there are also alignment issues with that approach.
I am wondering how I could make an array which contains arrays, but with a variable size.My first try..
Code:
int array[][] = {{1}, {2}};
But this isn't proper
I have a function like this
void foo( int i) {
...
uint8_t buf[ i];
...
}
And I don't understand why the compiler is not complaining... I'm using g++ -c -g -Wall to compile ....
I've been trying to store the inital size of a list in an int variable, so I can access it later in case I modify the list size. For example, I did the following:
std::list<AType *> myList;
myList.push_back(anATypeobject);
int initListSize = myList.size(); //initial list size
myList.push_back(anotherATypeobject);
myList.push_back(yetanotherATypeobject);
while(myList.size > initListSize)
myList.pop_back();
What this is supposed to do is to get an initial size of a list, and then be able to return to that initial size. However, when I try to do it in my code, initListSize always change if myList.size() changes. Is there a way to change that?
I am new to C. I've been trying to use C to code some statistical functions originally coded in R. I've encountered an interesting phenomenon. In the function foo1, I declared the array v1v2b using an actual value 1999000. The function runs fine when I call it in R.
Code:
void foo1(double *x, double *y, int *nsamp){
int i, j, k, oper=2, l;
double* v1v2=malloc(sizeof(double)*((*nsamp)*(*nsamp-1)/2 + 1));
outer_pos(x, y, nsamp, &v1v2[0]);
double v1v2b[1999000]; //<-------HERE
for(i=1; i<= 1999000]; i++){
v1v2b[i-1]=1;
} }
However, in foo2, I first create an integer variable called index, and store the value 1999000 in it. I then use it to initialize the same array. When I tried calling this function in R, it either led to a stack overflow error, or completely crashed R.
Code:
void foo2(double *x, double *y, int *nsamp){
int i, j, k, oper=2, l;
double* v1v2=malloc(sizeof(double)*((*nsamp)*(*nsamp-1)/2 + 1));
[Code] .....
For my default constructor I need to set an array of strings to null and the size variable to 0. Here is my code for that
DynamicStringArray::DynamicStringArray() {
*DynamicArray[]=NULL;
size=0;
}
When I try and compile it I get an "expected primary expression before ']' token" error.
I am having an issue with my sort function. This is one part of the Hash table program. The main issue is that I am trying to sort the pointer table after all of the values have been entered. The ptr_sort function is not a class function and so I am therefore unable to use the class variables psize and pTable. Is there another way I should be trying this? it is a Vector should I use the sort() function from the vector class in STL?
#include "/home/onyuksel/courses/340/progs/13f/p9/util9.h"
#include "/home/onyuksel/courses/340/progs/13f/p9/hTable.h"
#ifndef H_TABLE1
#define H_TABLE1
void ptr_sort ( );
[Code] ....
If a user enters a string of boolean algebra it will ouput the table.
I have input parsing, cycling through the combinations, and outputing working. However once i parse the input I am not sure what to do with it. I have thought of having it write the parsed input to a new file as a function and then use that function, but that seems bad.
How to dynamically create the function, how to implement it.
BTW This is a console function, if that changes anything.
I have written an SQL statement that would:
1) Count the number of rows in the table booking that are open and where the booking.postcode is "MK",
2) Take a note of the plot (in booking.plot_id), and then update the table plot.jobs with the value count.
For example running the SQL query when booking table has the following rows:
Would see the following highlighted values in plot.jobs being updated to 1:
I managed to resolve it with this code so far (note I am using Connector/Net):
public void RefreshPlot(){
string query =
"SELECT Count(*) AS count, plot_id FROM booking WHERE postcode='MK' AND status='open' GROUP BY plot_id";
var cmd = new MySqlCommand(query, _connection);
var da = new MySqlDataAdapter(cmd);
var dtCounts = new DataTable();
da.Fill(dtCounts);
[code]....
Currently, my code only checks for existing rows in the booking table and updates the plot table. However if the row gets deleted in the booking, then the changes are not reflected in the plot table.
Example: If we delete the row with plot.id=1 and plot.plot_id=4, then booking.plot_id should go back to being 0, if it was initially 1. At the moment, it doesn't. How would I update my SQL statement to better reflect this? In a sense, it should check for "non-existent" rows, i.e. the impact that the row plot.plot_id=4 & plot.id=1 has on booking.plot_id when deleted?
how to insert a variable for the size of array and prompt user to insert the elements for the array?
View 13 Replies View RelatedI have a C# .NET Application which get data from QuickBooks via the ODBC Driver and save the result to C# data table. So, I want to transfer this data table to a mysql table on my own server. That's the code I use:
using System.IO;
using MySql.Data.MySqlClient;
//Add mysql dll on the .NET Tab in Project's references
string connStr = "DSN=QBTest;";
string myServerAddress = "192.168.0.243";
string myDataBase = "CostTest";
[Code] ....
I am a bit stumped with trying to write some code to get the tableadapter/binding source to "update" a current 'user' to the table.
I have the insert/delete methods working fine, but it's the updating that has got me screwed up.
Example of insert.
try
{
personTableAdapter.Insert(tFirstName.Text, tSurname.Text, Convert.ToDateTime(tDoB.Text), tPhone.Text, tAdd1.Text, tAdd2.Text, tSuburb.Text, tState.Text, tPostcode.Text, TeacherType.Text);
teacherTableAdapter.Insert(Convert.ToInt32(tTID1.Text), tRegNo.Text, tPassword.Text);
[Code]....
I also tried to do the updated string/original string with the tableadapter.update, but that didn't work either.
Change the frame window size according to font size increases.
View 3 Replies View RelatedI must take an old MFC project in VC++ 6.0 and make changes.
The problem is text size in screen is different from size in print preview.
for example with this font
Code:
CFont f50;
f50.CreateFont(100,0,0,0,FW_BOLD,0,0,0,DEFAULT_CHARSET,OUT_DEFAULT_PRECIS,
CLIP_DEFAULT_PRECIS,DEFAULT_QUALITY,FF_DONTCARE,"Frutiger LT Std 45 Light");
And this text
Code:
s=_T("Let's try to calculate the size of this text");
and with MM_LOMETRIC map mode
GetTextExtent() returns me:
On screen: (1595,99)
Ink printer + print preview: (1589,100)
PDFCreator + print preview: (1580,100)
comparing with screen size the height is bigger but lenght is smaller. I don't understand.
I can understand that different printers process the fonts in different way and then to have different lenghts. That's not the problem. The problem is I need to simulate in screen the same behaviour i will have on printer because these texts are being aligned in the document, and I don't want to see that the text si aligned different in text than in paper.
What can I do to render the text on screen with the same size I will have on the printer? Print preview is doing it. Should I change the font parameters? is something related with pixels per inch?
I was wondering why, in C, the sizeof of a struct is larger than the the sum of all the sizeofs of it's members. It only seems to be by a few bytes, but as a bit of a perfectionist I fine this a bit annoying.
View 1 Replies View RelatedI would like to convert a float or double variable into unsigned char variable and back.
float number_float = 23.453f;
unsigned char* number_char = (unsigned char*)malloc(sizeof(float));
number_char = reinterpret_cast<unsigned char*> (&number_float);
float* number_float_0 = reinterpret_cast<float*>(&number_char);
I am not getting the same value back.. why?
I am having trouble compiling my interface. I am trying to store a reference variable as a member variable of the interface object. Compiler says that the variable has not be initiated correctly.
LCD inherits from VisualInterface which is expecting a DisplayDriver object to be passed in (DisplayDriver is another interface, but thats not important).
I pass the displayDriver object in when LCD is instantiated in maininterfaces.zip
I was pasing it before as a pointer but was told that this could cause me problems with memory leaks and a reference was better, but now I cant seem to get it to compile.