When a declare a string e.g.
Code:
char str[30]; as a global variable, the srting is initialized to NULL.
But if I declare char str1[30] INSIDE main(), then the string has garbage inside.... Why this happens??
E.g. the following code snippet...
Code:
#include <stdio.h>
char str[50];
int main(){
char str1[50];
[Code] ....
I need to transform a local variable into a global variable so I can use it in one of my functions. I thought about passing the value as a parameter to this function but I can do this since the function is called inside the while loop and this variable counts how many times the while loop does (so the final value is outside the loop). Example to visualize better:
Code:
while(condition) {
function(parameter1, parameter2);
count = count + 1;
}
printf("%d
", count);
So, I need to transform the final value of "count" into a global variable. Can I do this?
is it possible to have a global variable pointing to a different address depending on the thread?
Imagine one would like to use threads with the loop:
for (i=0;i<n;i++){
globalPointerVariable=getAddress(i);
DoThingsUsingThe_globalPointerVariable();
}
I got the following lines of code from a book. The variable char c is being used here to demonstration local variable declaration.
while(char c = cin.get() != 'q') {
cout << c << " wasn't it" << endl;
if(char x = c == 'a' || c == 'b')
cout << "You typed a or b" << endl;
else
cout << "You typed " << x << endl;
}
It compiles and runs. There are two issues when I try to run it.
1) It seems to loop through two times for every entry. If I insert cin.ignore() just before the closing bracket, it seems to work better.
2) the variable c does not seem to have the character I entered when examined in the if statement.
What is happening with the variable c inside the while loop scope?
Does c actually get initialized?
Code:
#include <iostream>
using namespace std;
void f() {
int x=17;
//cout<<main::y<<endl; i want to access y from main scope
}
int main() {
int y=23;
//cout<<f::x<<endl;
I want to access x from f scope is there any way for this without global declaration? specially about function scopes...
The problem that I want to make an array " vertextDegree [nbColours] " with " nbColours " elements in it ,but the "nbColours" unknown and I have to get it get it from a file .
Code:
int nbEdges,nbVetices, nbColours ;
typedef struct st_graphVertex {
int index;
int colour;
int val ;
int vertexDegree[nbColours]; // it won't work because nbColours unknown
// here and I want get it from file in the main
struct st_graphVertex *next;
t_edgeList *out;
}t_grapheVertex;
Here is the code,
Code:
class A {
};
A& CreateObject() {
static A a;
return a;
} static A aa;
int main() {
return 0;
}
So is there any difference between a defined in CreateObject and aa?
I came across the following code today and I was a bit surprised that it worked:-
Code:
std::string func_A () {
static std::string x;
if (!x.empty())
return x;
[Code] ....
I've simplified things slightly - but the basic point is that both functions are in the same source file and they both have a static std::string called 'x'. Being static, I guess they aren't (strictly) local variables. So how does the compiler know that they're different entities? Does it encode their signatures using the function name or something like that? If I call each function separately I do seem to get the correct string...
How can I declare global 'delete' operation multiple times? Like, I've an implementation of global 'delete' operation in a file 'x' but I want a different behavior in file 'y'. However, if I override it again in file 'y' I get multiple definition error.
View 3 Replies View RelatedHow can I convert these Global Declarations to only be Local?
#include <stdio.h>
#include <math.h>
int calculateArea(int num1, int num2);
double calculatePerimeter(double num3, double num4, double num5);
//Global Delcarations
float side1,side2,side3;
float area;
double perimeter;
[Code].....
#include<iostream>
#include<stdlib.h>
using namespace std;
int Name(),Minimum(),Maximum();
int main() {
int name=Name(),minimum= Minimum(),maximum= Maximum();
[Code] ...
There are error to let user to key in minimum and maximum values, i would like to know whats the problem?
Should i never return a pointer to a local variable. i have seen the following code in the standard text book.
Code:
struct node *add_to_list(struct node *list, int n)
{
struct node *new_node;
new_node = malloc(sizeof(struct node));
// some code here
return new_node;
}
new_node is a local pointer then why is he returning the new_node? Is it wrong or am i failing to understand something?
Here is my overloaded operator :
const double & Waz::operator()(int i,int j) const {
return ((WazImpl const)(*p))(i,j);
}
Where in Waz class I have : WazImpl* p; and in the class WazImpl I have an operator () const
The warning is : Warning C4172 returning address of local variable or temporary
As far as I understand I'm returning a temp variable which is destroyed somewhere else what can I do to fix it?
I know that this code is wrong because it returns the address of local variable which no longer exist after function:
int *f1()
{
int x = 2;
return &x;
}
However, why this one does not show problem and runs fine, here the pointer p is also a local variable:
int *f2()
{
int x = 2;
int *p;
p = &x;
return p;
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Furniture {
class Program {
static void Main(string[] args)
[Code] ....
I tried changing the type of variable to char but i still get the same result. i also tried using a switch statement which was my first choice but i had the same issue.
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] .....
{
//Declare Variables
decimal hrsWrkd, otPay, grossPay, taxRate=0, taxAmount, netPay,basePay, wage;
string maritalStatus;
const decimal WORKWEEK = 40;
const decimal OTRATE = 1.5m;
const double m = 0.15;
[Code] ....
The error message I am getting is Use of unassigned local variable 'otPay' . I see its been declared and been used in the code so the error is confusing, also when i run the program i noticed that it doesn't take out the taxes.
So I have been working my way through this assignment and I'm just stuck now. I cannot get this work properly It just tells me I'm trying to return a local variable when attempting to return postfix in the to_postfix function. It is line 97 that wont compile. Also I cannot change anything in runner.c.
Calculator.c
Code:
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <ctype.h>
4 #include <string.h>
5 #include "stack.h"
[Code] .....
#include <iostream.h>
#include <conio.h>
int main() {
int a;
cout<< "ingrese un numero entre 1 y 4 gracias
";
cin>> a;
switch(a)
[code].....
I am doing a piece of gui code on some embedded system.
I'm trying to find a way of eliminating the local variable kEvent:
Code:
EVENT kEvent;
....
Code:
kEvent = EVENT_UPSTREAM;
xStatus = xQueueSendToBack(getEventProcessorQueue(),&kEvent, 0 );
....
I tried this, it doesn't work:
Code:
xStatus = xQueueSendToBack(getEventProcessorQueue(),(EVENT *)EVENT_UPSTREAM, 0 );
Shouldn't this work?
Expected output: 20
But what I got is: 22
Why. While calling sub function it should take the global variable am I right
insert Code:
#include <iostream>
using namespace std;
int a=0;
void sub()
[Code] ....
Okay so I am programming an 8051 variant to interact with an SD card. In a separate initialization routine in SD_CARD.c I pull out the vital information of the card into global variables. I then call Menu() which is in another source file but includes a header file with all of the variables declared as extern. Now here is the weird, part this is from my Menu.c
printf("%u" , VOLUME_1_SECTOR);
if(VOLUME_1_SECTOR==16384)
printf("Correct");
else
printf("Incorrect");
Now the output of the first printf is 16384 but the conditional evaluates to false. If I put this code in SD_CARD.c (Where VOLUME_1_SECTOR is defined) the conditional evaluates to true. I am confused why the printf works correctly in Menu.c but not the conditional.
I want to make a destructor counter...So it needs to be outside that specific instance of the class. And i want to keep it hidden. I don't want to be able to access it from outside the class...I Don't want main.cpp to have access to this variable
Is there a way to do this?
static int destructorCount;
I have a small problem with my program. It is kinda a mess but I will try to explain you what I am trying to do. I have some threads. One of it, it attempts to detect a game client. So my code is sort of like that:
DWORD ProcessID; // The process ID of the game client
void test() {
char* text;
[Code]....
So basically, its like the variable changes, but only inside the thread... why does that happen?
I am getting this error while trying to compile my program:
It says that my variables "nome, cognome, eta..etc" are being used for the first time in my "inserisci" function.
I tought that I could just declare them as global in my structure like I did in my code, but apparently this doesn't work.
Do I really need to declare them again outside of my structure? Isn't there another way?
Here is my code:
#include <stdio.h>
#include "readline.h"
void inserisci(void);
struct impiegato{
char nome[20];
char cognome[20];
int eta;
[code].....
I have a .c file for each function of my program and i have .h,so how can I extern the following
in my main...
typedef int table[100][100];
how can I extern them in the .h and c files?
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#include <unistd.h>
#define HEIGHT 100
#define WIDTH 100
[code]....