C/C++ :: Jump Table Instead Of Switch Cases?

Aug 14, 2012

I have an issue with switch case. There are about 32 cases to be handled in switch. each case just assigns a hexadecimal to a local variable.

#define ADFV 0x0301
Switch(error_index)
{
case 1:
var = ADFV;
........
}
}

can i use jump table for above issue to reduce the code size.

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C++ :: Switch Statement Falling Through All Cases

Jan 16, 2014

I was getting errors and I looked into the error and it told me to fix it by adding Code: { } in my case statements. I did, it compiled but fell through the whole thing. Lets say I enter 1, it outputs the was not found 5 times in a row.

Code:
void addressbook::EditNameOrDate() {
std::cout << "Enter 1 to Edit the contacts First Name: " << "
";
std::cout << "Enter 2 to Edit the contacts Last Name: " << "
";
std::cout << "Enter 3 to Edit the contacts Street Address: " << "

[Code] .....

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C/C++ :: Optimizing Equation For Cases Of 0

Feb 19, 2015

I'm writing an algorithm on a microcontroller in C.

One of the iterations that takes a long time involves the following equation, summing the product of pairs of variables:

signed char VarA;
signed char VarA;
signed long VarA;
Total+=VarA*VarB;

The vast majority of cases, at least one of the variables VarA and VarB will be 0, so nothing will be added to Total.

Is there a way to check for this condition which might give me a performance increase over doing a lot of multiplying-by-zeros?

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C++ :: Why Cannot Jump Out Of For Loop

Jun 6, 2013

I got code like this:

#include <iostream>
#include <vector>
using namespace std;
const long nx(3);
const long ny(3);
const long seal(-1);
long TotP(0);
class pore {

[Code]...

I can print out all those TotP, but cannot get Finish loop print out, why? If I put any statement below, which seems won't be executed, it is like it never jump out from the loop and die inside.

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C :: Trying To Scanf A Char And Code Just Jump Over It

Jan 25, 2014

I'm doing a code to calculate the final grade of students. This is a work for college, and I need to keep this structure.

My problem is that last scanf, it is ignored when I compile the code. It "works" if I try to scan a string, float or int.

Code:

#include <stdio.h>
#include <stdlib.h>
void nfinal(float NOTA1,float NOTA2,float NOTA3,char MEDIA){
int NOTA;
if(MEDIA=='A'){
NOTA=(NOTA1+NOTA2+NOTA3)/3;

[Code]....

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C# :: How To Jump From One TextBox To Next When Press Enter Key

Apr 13, 2014

How can i jump from textBox to next texBox when i press enterKey in c# , what i the event for that .....

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C/C++ :: Conditional Jump Or Move Depends On Uninitialized Value(s)

Nov 24, 2014

I am getting this message from Valgrind, As far as I can see what it points to is initialized. The memory it is referring to is freed in unload and I was not getting this error until after I added the check function. Valgrind was happy. Here is the code and the error message from Valgrind. I am trying to create a spell checker for an assignment for a online class I am taking. I just want to get this table working correctly before I add it to the rest of the program. The code seems to run fine but I have come to see that dos not mean much in C.

#include "hashTable.h"
#include <stdbool.h>
table_node hash_table[TABLE_LENGTH];
bool loaded = true;
//assigning letters a-z to table nodes for buckets
void key_hash_t( )

[Code] ....

Valgrind error:

arortell@gentoo ~/Development/Projects/C_Projects/Data_Structures/HashTable $ valgrind --leak-check=full --track-origins=yes ./hashTable
==11360== Memcheck, a memory error detector
==11360== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==11360== Using Valgrind-3.9.0 and LibVEX; rerun with -h for copyright info
==11360== Command: ./hashTable

[Code] ....

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C++ :: Conditional Jump Depends On Uninitialized Value Valgrind

Jan 10, 2013

I have airport class which should navigate planes, in its list to runways, with method move, theres a method prepare which changes the direction of flight to all planes, always before move is called, move just increments decrement x and y of plane in its list. But after calling two times in row airport->move(), I get screwed and I really dont know wheres the problem. Have I badly initiazed something? Iterator gets invalidated.

Valgrind Stacktrace
Conditional jump or move depends on uninitialised value(s)
==26207== at 0x409601: plane::move() (in /home/xnovak11/Downloads/airport/main)
==26207== by 0x401FBD: airport::move() (in /home/xnovak11/Downloads/airport/main)
==26207== by 0x405FE1: io::start(std::istream&, std:stream&, std:stream&) (in /home/xnovak11/Downloads/airport/main)

This is how I add planes into list in airport

Code:
list<plane*> planes;
list<plane*>::const_iterator planeIterator;
list<plane*>::iterator planeIteratorMoj;
bool airport::addPlane(const plane& p) {

[Code] .....

This is the method where it fails. When I call it once, no problem, after second call I get instead of normal number in cout<<after move<< s1 i get like 8795456 ....

Code:
void airport::move() {
for(planeIteratorMoj = planes.begin(); planeIteratorMoj!= planes.end(); planeIteratorMoj++) {
plane * p1 = (*planeIteratorMoj);
int s,w;
p1->getPosition(s,w);

[Code] .....

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C :: Use Switch Case As A Menu To Switch Between Patients

Dec 30, 2014

I am trying to make a program which manages the data of 5 different patients (its an uni assignment), and i want to use a switch case as a menu to switch between the patients. All other functions (as for example putting the infromation on a file) work, but i cant figure out to bring the switch to work. First it asks for the number of the patient which should be worked with, this works perfectly, but afterwards changiung between the persons doesnt work as thought. It should ask everytime after it switches to one patient (i removed some functions to make it easier to read) and then asks to which it should jump next. If i put the number of one case (lets say 3) it just stops the program.

********Example:
user@pc ~/wherever $ ./program
current variables:
jo = 2
a = 0
1 //the entered number
The variable a = 1
patient 1
Enter the number of the next patient2
// and then it closes
**************

The same thing happens if i compile an example code from a book, it writes the first case and then stops.

I looked already through the forum but didnt find a person with a similar problem, maybe i didnt dig deep enough.

I am running Linux Mint 17 and use gcc as compiler.

Code:

include <stdio.h>
#include <stdlib.h>
int a=0;
int jo=2;
int main(void){
printf("current variables:
jo = %d
a = %d

[Code]...

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C++ :: Hash Table Program - Sorting Pointer Table After All Of Values Entered

Nov 19, 2013

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] ....

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C++ :: Truth Table Generator - If User Enters String Of Boolean Algebra It Will Output Table

Jan 25, 2013

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.

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C# :: Lookup Non-existent Rows In MySQL Table And Then Update Another Table

Dec 15, 2014

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?

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C Sharp :: Copy Data Table To MySQL Table

Mar 25, 2013

I 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] ....

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C# :: Use Table Adapter With Textboxes To Edit SQL Table?

Mar 8, 2015

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.

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C :: How To Use String And If Or Switch Together

Oct 11, 2013

How to use string and if or switch together

I want to make something like some users using the same machine so they need to be registered to the system and the their id something like this (H510698541) and their information should appear on the screen.

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C++ :: From If Else To Switch Statement

Mar 6, 2013

I was wondering how you would put this if else statement to a switch statement.

void PlayerDB::AddPlayer(const Player& avatarPlayer) {
char * playerName = new char[avatarPlayer.lenName()];
Player*player = NULL;

[Code] ....

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C++ :: Switch Statement Is Not Working?

Aug 16, 2014

okay so like case 2 and 3 is not working, also the program is still not finish but why isn't case 2 and 3 not functioning well on the switch part? case 1 works just fine

Code:
#include<stdio.h>
main ()
{
//passcode part (passcode is 1234)

[Code].....

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C :: Possible To Switch Two Array Positions?

Feb 12, 2015

I have a fundamental question due to my lack of understanding how arrays work.Let say I have a character array (byte array).

1. do array elements have memory adresses? i guess not but ....
2. if yes is it possible to switch two array positions? For examle:

a[x] change with a[y] for x,y < |a|

as oppose to changing values assigned to individual array positions.

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C :: LED Switch On When Error Detected?

Jul 9, 2013

I'm currently doing a project which will trigger an alarm and light up an LED when a character 'E' is detected from a bluetooth input. I'm supposed to program a pic18f4525 board.

I'm having troubles with where to start on the codes to enable the LED to light up upon detection of character 'E'. I'm using ports RD0-RD3. This is how I initialised them in the main loop.

Code:
TRISD = 0b11000000;
PORTD = 0xC0;

Am I doing the initialising right? Also, how to program it to light up when the character's detected?

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C :: Operators In Switch Statements?

May 20, 2013

Switch case statements are a substitute for long if statements that compare a variable to several "integral" values ("integral" values are simply values that can be expressed as an integer, such as the value of a char).

So does that mean switch statements can only test if variable == value and nothing more, like > < >= <= != etc... ? I tried to make a program to test this and it seems like switch statements are limited to == but I'm not sure, maybe I'm doing something wrong.

This is the program I tried to make to test this:

Code:
#include <stdio.h>
int main () {
int n;

[Code]....

So is it true that switch statements only work with the built in == operator? if that was the case then I would feel rather meh about switch statements.

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C :: Switch Statement Array

Apr 15, 2014

so I am trying to have an switch statement array. but every time i complete a case statement the whole process is returned. the thing is i want the menu to stay up even if i complete the case.

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C++ :: Switch Statements In GLUT

Jan 3, 2014

I'm making a game in OpenGL GLUT. A ball is going to move forwards along the Z axis and hit a wall. I want to be able to move the ball left and right, up and down before firing it off on the Z axis. I'm using glutSpecialKeys for this, and I've got everything set up, but I'm not sure how I use it with a switch statement? Here is a snippet of code:

void Special_Keys (int key, int x, int y){
switch(key){
case GLUT_KEY_UP: //do something
break;
case GLUT_KEY_DOWN: //do something

[Code] .....

Where the comment is saying "do something", I'm not sure what I actually need to do? Is it a method or what?

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C++ :: How To Link A Switch Statement To A If / Else

Aug 8, 2014

The sample output of this program would be:

Please select:
1 - Year
2 - Day
3 - Month
Input choice: 1
Input Number: 2
I'm a Sophomore!

Please select:
1 - Year
2 - Day
3 - Month
Input choice: 2
Input Number: 2
It's Tuesday.

Please select:
1 - Year
2 - Day
3 - Month
Input choice: 3
Input Number: 2
February. Heart's month!

Here is my code, I only typed the Year(levels) yet because when I tried to input 2(day) and 3(month) for the Input choice and after that, Inputting a number to 1-4 would yield the same result to case 1's year levels.

#include <stdio.h>
#include <conio.h>
using namespace std;

[Code].....

how to link the case 2 to days and case 3 to months?

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C++ :: How To Use Getline With Switch Statement

Sep 17, 2014

I have a problem with the switch statement because it doesn't prompt me to input something.

#include <iostream>
#include <fstream>
#include<cstring>
using namespace std;
//Compiler: Dev C++ and cygwin
void rd() {
string txt;

[Code] ....

I want to get rid of this kind of output ...

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C++ :: Converting If / Else To Switch Statement

Oct 8, 2014

if( vehicleUse == 'C' ) // Carpool
{
// TODO: Convert to a switch statement

if( vehicleLoad == 'E' ) // 6-8
cout << "Ford Windstar" << endl;
else if( vehicleLoad == 'F' ) // 8-10

[Code] .....

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C++ :: Compare Value In Switch Statement?

Sep 23, 2013

is it possible to compare value in switch statement? i.e: a > b

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