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]....
I have 3 files: f1.c f2.c and f3.c
I have declared variable int a; in f1.c and int a; in f2.c.
Now I want to use the variable int a; in f3.c . But this variable corresponds to the variable in f2.c .
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?
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.
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;
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 am making two classes using the juce library [URL] ....
this is a problem that has now come up after solving an earlier problem i posted but its a completely seperate issue.
i have a class for loading a file when i button is clicked that seems to work. Here is the function in my LoadButton cpp:
void LoadButton::buttonClicked(Button* button)
{
FileChooser pedoFileChooser ("Choose an Audio File", File::nonexistent, String::empty, true);
if (pedoFileChooser.browseForFileToOpen())
{
File pedoFile (pedoFileChooser.getResult());
}
}
I want to be able to then use the file stored in pedoFile in the cpp of another class called PlayButton. I tried doing this with a pointer? not sure if that's correct way of doing it (i know very little about C++ or programming) by changing the function to this. I'm getting the error invalid initialisation of non-const reference of type 'juce::File*&' from a temporary of type 'juce::File'
void LoadButton::buttonClicked(Button* button)
{
FileChooser pedoFileChooser ("Choose an Audio File", File::nonexistent, String::empty, true);
if (pedoFileChooser.browseForFileToOpen())
{
File* &pedoFile = (pedoFileChooser.getResult());
}
}
//I dont understand this why does "<< "
The value of global now is: " << global << "
";" is equals to nine
#include <iostream>
int subtract (int a, int b);
int global = 5;
int main(void) {
using std::cout;
int a, b;
[Code] ....
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...
I am trying to create a global array with user-defined dimensions.the code is:
Code:
int matr_size()
{
int x = 0;
printf("Please enter the number of nodes: ");
scanf( "%d", &x);
printf("There are %d nodes in this simulation.", x);
getchar();
return x;
}
[code]....
I read that an array cannot be defined by a variable in C so I assume that is the issue, but I'm not sure how else to do it. Previously the size was defined by #define NODES and it worked fine but I need this user input.
If I define the variable 'total', everything works well without any problem. But if I define it inside the function 'sum', I get irrelevant results, because each time the function gets executed, the variable total gets defined again, losing its value already assigned to it.
Do I have to use a global variable? Is there any way that I can do with without using a global variable?
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int total;
int sum(int a, int B)/>{
if (a < B)/>{
//printf("The total is %d, a is %d, and b is %d", total, a ,B)/>;
total += a;
[Code] ....
Ok so when the program runs the first function the data is stored and displayed in the file. The second function is supposed to read the name entered, compare it to the ones in the file then take the price with it BUT I seem to have done something wrong when reading the files (or maybe it has to do with the global function I'm not sure). Here's parts of the code :
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <string.h>
[Code]....
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();
}
If I DEFINE a global variable in two source files which belong to the same project, then there is a linker error "multiply defined symbols". But if I DEFINE a global variable in two source files which belong to the different projects, then it compiles fine. Why?
View 8 Replies View Relatedis there any variable type(or with another keyword) that we can change it's value in global scope?
View 5 Replies View RelatedHere 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'm trying to run so called student-administration program.I got functions that can read and write student data, but the one saving the data from about 30 students has some problem that I can't figure. (warning: I'm quite new to C programming)so this is the code:..I guess I can't use global variables as function arguments?
Code:
//global variables
static char ReturnName[31];
static char ReturnFirstName[31];
static float ReturnAverage;
}
[code]....
incompatible types when assigning to type 'char[31]' from type 'int'
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 have already defined two arrays:
int songId[15];
char typeOfSong[15]
For my assignment we HAVE to use typedef to declare these. I tried a multitude of combinations using typedef, but then the rest of my code that uses songId and typeOfSong is not valid. How would I set up the correct arrays using typedef?
I have made VGA emulation with registers and memory in my emulator. But for some reason the writes to the union array with CPU data (register 0-8 of the VGA's Graphics Controller Registers, referenced with <GRAPHREGS>.DATA[index]) don't reflect on the union's data.
typedef union __attribute__((packed)) {
byte DATA[9]; //9 registers present!
struct //Contains the registers itself! {
//Set/Reset Register (index 00h)
union {
[code]...
what's going wrong? Have I made an error in the registers?
(In this case I write to register <GRAPHREGS>.DATA[8] (which should be the <GRAPHREGS>.REGISTERS.BITMASKREGISTER)), but the BITMASKREGISTER stays 0, while DATA[8] gets the correct value.
I'm given a mathematical function F(x) = etc..., the user inputs an initial x point and a final x point. The program finds the integration.
Below is a snippet of code.
/*Typedefs as given by prof*/
typedef double (*mainFunction) (double);
typedef double (*calcArea) (mainFunction, double, double);
int main () {
answer = calcIntegral(mainFunction *curve1, calcArea *calcAreaRect, a, B)/>; /*it doesn't like this line*/
printf("The integral from %lf to %lf is: %.4lf", &a,&b,&answer);
return 0;
}
curve1 is a function that accepts a double and returns a double, calcAreaRect takes mainFunction main(which is F(x) so i stored the fn in curve1), double and double.
I have some complex declarations to simplify with typedef I have done a try
1. Code:
char (*x[10]) (int);
/* typedef char FUNC(int);
typedef FUNC *FUNC_PTR;
FUNC_PTR x[10]; */ Why we don't use * symbol in the last statement in front of FUNC_PTR?
2. Code:
int (*x(int))[5] I can't do this :/
3. Code:
float *(*x(void))(int);
/* typedef float *FUNC(int);
FUNC *x(void); */
I need to create the following brain damaging abomination:
I need a function pointer type to a function that has an argument of the same function pointer type and returns the same function pointer type.
The purpose is to enable a type of subroutine threading scheme for a small application specific scripting language. The question could just as well have been posted to the C forum.
This syntax works, but Payload is a generic type which I can coerce into the right pointer type via a cast. This is ugly IMHO. I could also hide it as a pointer in the FlipState class since I've forward declared this.
But this is an extra indirection in a performance critical part of the code, and also ugly.
Code:
class FlipState ;
typedef PayLoad (*FuncPtr) (FlipState *fs, PayLoad P) ; This syntax blows chunks using gcc on the other hand. Code: class FlipState ;
typedef FuncPtr (*FuncPtr) (FlipState *fs, FuncPtr P) ;
[Code] .....
This is hardly surprising. The compiler could not possibly understand what I was defining in the typedef. I think what I need is some kind of way to forward declare a function pointer type and then redefine it properly.
Is such a think even possible or am I just SOL? This one is mind boggling. We know how to do this with classes or other complex data types, but the syntax eludes me for both C++ and C.