C++ :: Compiler Auto Correct Uninitialized Variable?
Jul 13, 2012
I had a flawed function like this:
Code:
fn(){
char c;
if (runFirstTime){
#ifdef VC
c='';
#else
c='/';
#endif
}
... // c is used in the rest of the function to construct some pathnames
}
The problem is that the value of c is not defined the 2nd time the function is called (and subsequently). It somehow worked fine under CygWin compiled with gcc. So I didn't spot the flaw until it ran incorrectly under Windows complied with VC++ 2010. Then I found the error and changed the code to something like
Code:
fn(){
#ifdef VC
const char c='';
#else
const char c='/';
#endif
...
}
So now it works correctly under Windows. Then I re-compiled the new code with gcc and to my surprise gcc produced exactly the same binary! How can this be? Does the gcc compiler see my flaw and fix it for me somehow?
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Jan 8, 2015
#include <iostream>
#include <string>
struct WeatherStats {
double total_rainfall;
int high_temp;
int low_temp;
int avg_temp;
[Code] ....
When I run this program I am able to input data for the three months but after inputting everything I am prompted with a run time error that states: Run time check failure#3: The variable 'temp' is being used without being initialized. I've underlined the statement that the compiler says is causing this error, yet there is no variable 'temp' in that statement.
Computer are very specific right? So in the problem statement total_yearly_temp = total_yearly_temp + temp.avg_temp; there is a variable called total_yearly_temp and one called temp.avg_temp, but there are none called temp. It can't be complaining about the WeatherStats variable I defined in the first line of the function called temp because I did the exact same thing in the previous function and there are no errors concerning that.
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Sep 7, 2014
I keep getting the "Uninitialized Local Variable" error. But for my code it's says it's the variable 'pay' in my Manager Function. This is the only error that is popping up.
I've tried setting pay to 0 but when I do, I get a bunch of external errors. I've also tried assigning pay to WeeklySalary like this:
double pay = WeeklySalary;
//Calculating pay for a company
#include <iostream>
#include <iomanip>
using namespace std;
//Function prototypes
double managerFunction();
double hourlyWorkerFunction();
double commissionWorkerFunction();
[Code] .....
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Mar 27, 2015
In Visual Studios I keep getting this error. cpp(36): error C4700: uninitialized local variable 'Eligible' used
Code:
#include <iostream>
#include <string>
#include <iomanip>
#include <fstream>
#include <cmath>
using namespace std;
void Getinput(int& Loantype, double& Income, double& Totaldebt, double& Loanamount);
[Code] ....
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Feb 3, 2013
what compiler that change all variable in one occurrence?
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Feb 16, 2012
This code is for (hospital management system).
This code allow you to add patients.
There are two types of patients. which is:
1. Normal patient.
2. Critically ill patient.
once you added any patient. You will be able to show all patient using "ShowAllPatient;" method. -> i want the Auto-increment ID Number to appear for each patient has been added.
And you will be able to call a patient to provide a hospital services for him/her using "GetNextPatient;" method.
I need to generate an Auto-increment Number for each (patient) has been added. (Auto-increment Number) but it just should be different for each patient. For example the first patient will have 1, The second patient will have 2. etc. The Auto-increment number should appear for each patient.
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Oct 12, 2013
I have an example where I have a variable belonging to a base class, but I would like to tell the compiler that it actually belongs to a derived class. How can I do this?
// base class: R0
// derived class: R1
// see function SetR1 for the problem
class R0 {
public:
int a;
[Code] .....
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Aug 7, 2013
I have a structure
Code: struct time{
char hours;
char minutes;
char seconds;
char dummy;
};
I have kept dummy as the data to be aligned.I will update hours, minutes, and seconds , but will not use dummy in any case.
If I don't initialize 'dummy' does it make any errors ?
Do I need to initialize hours, minutes, seconds as well before I use the structure ?
If so is there any particular reason ?
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Aug 7, 2013
Let me say I have a structure
Code:
struct time{
char hours;
char minutes;
char seconds;
char dummy;
};
I have kept dummy as the data to be aligned.I will update hours, minutes, and seconds , but will not use dummy in any case. If I don't initialize 'dummy' does it make any errors ? Do I need to initialize hours, minutes, seconds as well before I use the structure ? If so is there any particular reason ?
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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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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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Aug 2, 2014
I discovered valgrind and started using it for my c code. But I get following error message at almost every malloc position, :
==19505== 40 errors in context 10 of 12: ==19505== Use of uninitialised value of size 8 ==19505== at 0x10000416E: my_method (main.c:662) ==19505== by 0x10000159E: main (main.c:182) ==19505== Uninitialised value was created by a heap allocation ==19505== at 0x47F1: malloc (vg_replace_malloc.c:302) ==19505== by 0x100001C21: my_method (main.c:333) ==19505== by 0x10000159E: main (main.c:182)
and I really don't understand what it means. I already googled it but I didn't find out what is my mistake.SO here i just put one example:
Code:
int main(int argc, char** argv) {
//i declare my variables at this position
Uint *used, *forbidden_jumps, *forbidden_jumpsV,
*forbidden_jump;
/*now i want to allocate one of them, this is my line 333 from the error message*/
//a_num is set during the execution of the program,
ALLOC(used, Uint, a_num);
}
[code].....
Is there any support page for the output of valgrind? I found it on the homepage.
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Apr 20, 2014
Is there a way to auto align a cpp file?
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Jan 28, 2014
Code using auto-implemented property:
public class MyClass {
public int age { get; set; }
}
static void Main(string[] args) {
MyClass testing = new MyClass();
testing.age = 44;
Console.WriteLine(testing.age);
}
output: 44
Code using regular variable declaration:
public class MyClass {
public int age;
}
static void Main(string[] args) {
MyClass testing = new MyClass();
testing.age = 44;
Console.WriteLine(testing.age);
}
output: 44
Why use the auto-implemented property when you can just as equally use the second code block to achieve the same thing?
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Apr 24, 2014
I write these code in 2 different ways and I get the same result. I just want to make sure that they both are for declare a pointer using "auto"
The first one:
int varName = 10;
auto var1 = &varName;
cout << var1 << endl; //prints, varName address
cout << *var1 << endl; //prints, varName value
The second one:
int varName = 10;
auto *var2 = &varName;
cout << var2 << endl; //prints, varName address
cout << *var2 << endl; //prints, varName value
It doesn't matter if I put dereference operator or not, I still get the same result. I just want to make sure that var1 and var2 are both a pointer.
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Jun 7, 2012
I'm having trouble with auto and decltype.
void f(const vector<int>& a, vector<float>& b) {
typedef decltype(a[0]*b[0]) Tmp;
for (int i=0; i < b.size(); ++i) {
auto p0 = new auto(a[i]*b[i]);
auto p1 = new decltype(a[i]*b[i]);
[Code] ....
The above code runs well in GCC4.7.
Could I use 'new auto(a[0]*b[0])' to allocate memory for the type of a[0]*b[0]？
And I can not distinguish the difference between decltype and auto in this case.
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Jan 6, 2013
I presently use the turbo C++ IDE. it has the red background(changeable) and all that but it does not have auto completion for curly braces.
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May 31, 2013
Okay so what I want to do is :- Create a program that can, say for example, switch to an already opened up google search page. Type in a given string and press enter.
Once more. The google search page is open.[Type anything on google.com and then THAT next page is the one ..] **So , the search box ,where you enter text has fixed coordinates.. (Which website doesnt matter, only coordinates do!)
I want the mouse to go to those coordinates, *click* and now a cursor will appear on the search box.
After this I want to send a fixed string output...That is , it should actually type in the string in that search box. then press enter.
That's it . [P.S. - obviously I don't want to do this with google, that was just an example.]
Mini Algorithm-
1)Get the mouse pointer to the x-y coords
2)Click!
3)Type in the fixed string.
4)Enter..
I can put it in a loop, don't bother with the easy bits I need to know how to control the mouse, and how to send the input string. Code snippets would be perfect
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Jun 1, 2013
Create a program that can, say for example, switch to an already opened up google search page. Type in a given string and press enter.
Once more. The google search page is open.[Type anything on google.com and then THAT next page is the one ..] **So , the search box ,where you enter text has fixed coordinates. (Which website doesnt matter, only coordinates do!)
I want the mouse to go to those coordinates, *click* and now a cursor will appear on the search box. After this I want to send a fixed string output...That is , it should actually type in the string in that search box.
then press enter.
Mini Algorithm-
1)Get the mouse pointer to the x-y coords
2)Click!
3)Type in the fixed string.
4)Enter..
I can put it in a loop, don't bother with the easy bits I need to know how to control the mouse, and how to send the input string. Code snippets would be perfect .
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Nov 14, 2014
Right now I am trying to make an alarm clock type program that will start on login and will go off when a certain time is reached. I also want to set a password that will prevent system use until the correct password is entered into the program's input. What functions will I need and how are they used?
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Mar 28, 2014
I'm trying to code a program in Dev-C++ for auto complete text in a web form. I'm using windows.h and mouse_event() function for move cursor position and click buttons, but I need write in a inputs/textarea a text.
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Jan 22, 2014
Background: I'm making a small game using CodeBlocks and SDL. All of the code resides in a class named Game - the only thing running in Main is the creation of the Game object and the class function execute(). So far, I've made a Start Menu with three clickable buttons. I'm in the midst of making one of the buttons - Load Game - change the game screen to the Load Game menu. Basically, when the user clicks the button, the image on screen changes according to the button they click.
Issue: After successfully making the Load Game button change the image on the screen, I found that the SDL window mysteriously closes out several seconds after the image change. What is causing this - the window stays on perfectly fine until the background image is changed and the only way to break the loop is for the player to click the x on the window. I've gone over the code several times and haven't found anything that might be the cause.
Code:
Game.h file
#ifndef GAME_H
#define GAME_H
#include "SDL/SDL.h"
#include "SDL/SDL_ttf.h"
#include <iostream>
#include <cstdlib>
[Code] ....
Output:
- Window with an Start Menu image and a button with the words "Load Game".
- If user clicks the X on the window, the window closes.
- If user clicks "Load Game" button, Start Menu image changes to Load Game image. After about seven seconds, the window automatically closes out. This isn't supposed to happen.
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Nov 5, 2012
I created a table called registration and I have set an auto increment ID for each record. The problem is when I delete a certain record the ID didn't remove or deleted, for example if I entered these records: -
1,Bob,Bob123,Bob_2@hotmail.com then if I deleted it the next id record will be 2 which is supposed to be 1.
here is the SQL Command:-
CREATE TABLE Registration (
Reg_Id INT PRIMARY KEY IDENTITY,
Name varchar (255),
UserName varchar(255) NOT NULL,
Reg_Password varchar(255),
Email varchar(255),
Reg_Rank varchar(255)
);
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Oct 27, 2014
I wanna store my data by descending order auto without doing a classification after , i have come up with a code but it crashes.
Code:
void list::create(int num) {
struct node * n,*temp;
n=new node;
n->data=num;
if(head==NULL)
[Code]....
I don't wanna use the list library with the push.buck, i need to do it by coding it without fix functions ....
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Jul 23, 2014
I thought I'd display my fun use of the new C++11 auto keyword to create a compile time foreach. It only works for STL collections, or anything that implements the STL collection iterator methods begin(), end() that return a STL iterator.
// Standard Template Library foreach
// element = iterator name
// collection = STL data collection variable
#define stl_foreach(element, collection)
for(auto element = collection.begin(), __end__ = collection.end();
element != __end__; element++)
}
[code]....
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Feb 9, 2013
Apparently the default behavior with Direct2D when rendering is to scale everything I render based on the size of the render target/window. How can I prevent this? I want to decide for myself when to scale the image, regardless of the size of the window.
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