I want to know
prog1.c
#include<stdio.c>
static int c=6;
int main() {
/*code*/
}
prog2.c
#include<stdio.h>
int main(){
static int c=10;
}
what would be the difference between these two program in the fuctioning of static keyword ?
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?
What is difference (memory allocation or any) between declaring a variable inside or outside the variable
program1:
#include<stdio.h>
int main() {
int i;
for (i=0;i=<100;i++) {
[Code] .....
Difference b/w program1 and program2. Its look both are same. but my compiler shows something difference.
Say you had:
class Foo{
public:
//...
void funky();
[Code] .....
Would each instance of Foo create a new counter variable, or would it remain the same for all of them, i.e. baz.funky() would always use the same counter variable? What if the class was a template?
I am modifying a set of static variables inside of the class's member function. The static variables are private. An example of what I'm doing is as below,
utilities.h
-----------
class utilities {
private:
static int num_nodes;
public:
void parse_details(char* );
[Code] ....
I get a compilation error in the function void utilities::parse_details(char* filename)
which says: undefined reference to `utilities::num_nodes'
compiler: g++
I am trying to run a programme implementing a function with structures in c... which is:
#include<stdio.h>
#include<conio.h>
struct store {
char name[20];
float price;
int quantity;
[Code] .....
What are the workarounds for accessing the non-static member variables of some class(Say A) inside static member functions of another class(Say B)? I am coding in c++. Class A is derived with public properties of class B. Any pointers?
View 7 Replies View RelatedHave following code:
class Program
{
static void Main(string[] args)
{
[Code]....
My question according to what i just wrote:
1. Is that mean that Do() is only available for use by Dog itself because Dog is 'oryginal' Dog, and if i create new dogs - instances of oryginal Dog (dog1, dog2 ...) they cant access because Do is only available fo 'oryginal' one? Is that correct thinking?
2. If i would want to have something common (e.g value) for all dogs is that good way to create static field/method for Dog instead of non-static once then all instances of Dog would access Dog static member to get/change it? Just stupid example: static method GetAmountOfLegs() which return 4 Then all instances can take/call that value from Dog. Is that correct thinking?
class Hallway {
private:
//---------------------------------------------------------------
// DO_04: Declare a Light array of size MAX_LIGHTS
// Hint: look through the methods below to find the name to use
// for the array
//---------------------------------------------------------------
int numLights;
int lights[MAX_LIGHTS];
[Code] .....
I keep getting the error " this.lights[i] is not a struct or class and so you cannot use '.' " on line 34.
How am I supposed to define my lights[] array? I can't modify anything except directly after each comment block.
I notice I keep making the same mistake of not declaring certain objects, variables or lists inside the constructor so they e.g. a list populates when the view loads.
Which makes me think about it this way. Why do I need the constructor and when do I declare objects inside the constructor?
Maybe it just comes down to me not understanding the fundamentals of how to utilize the constructor.
I just wanted to know what's the difference between these two types of main functions:
Code: int main (int argc, char** argv){ ... }
Code: int main (int argc, char* argv[]){ ... }
what is main difference between the static array and a dynamic array....also i am confused with dynamic array and dynamic allocated array?
View 3 Replies View RelatedIs there a difference between having static and dynamic cast in this scenario? The output is the same.
Code:
Base* pb = new Derived();
if(Derived* pd2 = static_cast<Derived*>(pb)) // true {
pd2->get_price(); // calls Base::get_price()
pd2->get_rate(); // calls Derived::get_rate()
[Code] ....
i'm still unclear between the difference between using pointer and a reference
I understood the concept of pointers in c in the class i took last year
and that was to change the actual value stored in the memory address Code:
void change_a(int a*){
a=6;
}
int main(){
int a=5;
change_a(&a);
}
but in c++ I've been using references in all my assignments because I don't know how to correctly use pointers in c++ I may have missed a class but I'm on spring break and would like to clear things up
so in c++
in my assignments I would call it like this Code:
void change_a(int &a){
a=6;
}
int main(){
int a=5;
change_a(a);
}
so does this change the value in the address or does it make another copy of a in my c++ code and stores 6 in that copy
I am writing a program where all work is done in the class methods. Main is used to call the methods. I need to know how to get a loop to work without any variables in main that can be used outside the methods. This is what I have in main:
#include <iostream>
#include <string>
using namespace std;
#include "FerryBoat.h"
int main() {
//create a constructor for a ferry boat
FerryBoat myBoat('B', 20, 'A');
[Code] ....
This is a program I developed in which we had to define a class named BOOK with the data members and member functions as shown in the program..We have to:
(i) Make the user enter the values in the array BOOK.
(ii) Display the details that the user entered.
(iii) Search for a book from the array upon its Bno and display its details.
(iv) Search for a book from the array upon its Bname and display its details.
PROGRAM:
#include<iostream.h>
#include<conio.h>
#include<stdio.h>
#include<string.h>
class BOOK {
private:
int Bno;
char Bname[20];
[Code] .....
But while running it the compiler gives the errors as:
Line 43 to 48: Illegal character '' (0x5c)
Line 69: Undefined symbol 'Display'
Line 88: 'BOOK::Bno' is not accessible.
Line 89:'BOOK::Bname' is not accessible.
Line 90:'BOOK::Author' is not accesible.
Line 91:'BOOK::Price' is not accesible.
Line 108:'BOOK::Bno' is not accessible.
Line 109:'BOOK::Bname' is not accessible.
Line 110:'BOOK::Author' is not accesible.
Line 111:'BOOK::Price' is not accesible.
from 43 to 48..the line feed was also used at many other places but there it was not given as an error so why here?
Line 69: I defined the Display() function outside the class since it contained control structures, so what's the error then?
About the lines the rest of the error( the "not accessible" ones) I know these data members are not accessible because they are in private visibility mode. But then how to make them accessible? (Without putting them in public because it was a part of the question to create the data members in private).
Code:
#include <stdio.h>
int main(void){
int a=0;
for(;a<=10;)
int b;
return 0;
}
I have got a code like this. I don't expect to get an output but just assumed I would see the command screen until I terminated it. What I want to do is just declare a variable b in a endless loop. But what I got from the compiler is this error: error: expected expression before 'int'. I am using Code::Blocks and I think the compiler is GCC.
I wanted to ask if it is somehow possible to do:
Code:
class RaspberryPi: public Singleton<RaspberryPi> {
private:
static const DeviceInfo GPS;
template<typename Register_t>
auto ReadGPS(Register_t& Register) -> void
[Code] ....
There are two limitations I am facing:
First, it seems that anything that is part of a struct cannot be a compile-time expression. It's a nice way to group information, so it would be nice to have.
Secondly, it seems that all compile-time expressions cannot be inside a class (at least according to VC++), which means I have to move them to global level, but while it can be done, I don't really want to do it, because it's a platform detail.
In this case, static type dispatch would be nice to have because I have a function
Code:
template<typename Register_t>
auto ReadBus(Platforms::DeviceInfo Device, Register_t& Register) -> void {
switch (Device.Bus)
[Code] .....
There are two types of registers. With runtime dispatch, I get disgusting errors such as "could not deduce template arguments, blah blah" if some object doesn't have the required interface (i.e., don't have overloads for both register types). So the workaround would be to add two overloads and use something like asserts to stop invalid code from running, but it would be so nice to only allow correct code to compile and not get scary error messages.
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] .....
I am having following pointer variable declaration
Code: Static double (*funcs[]) (double) = { sin,cos,tan,asin,acos};
Here funcs is an array of pointers to functions which take double as input and gives double as output with static as storage type am I right.
I'm currently writing a poker game and am trying my best to avoid using global variables. I have a few variables in int main() which i was hoping to use to store the value of each players hand. I then created a function which calculates the value of the hand but cannot get this value back into the main function.
For example:
Code:
#include <iostream>
using namespace std;
void getValue(int value) {
value = 4;
[Code] ....
Is there any way i can get the value of value using this function? If not what can I do?
This code is for a program that allows you to play a guessing game or arithmetic game and shows your total score from both as you go along. The program works fine the only problem I'm having is with the score. Is there a way to call the score value from the outside function into main?
Code:
#include <stdio.h>
#include <time.h>
#include <stdlib.h>
//prototype functions
void menu();
[Code] .....
So trying to pass the value of score from the outer function int guessGame() into the score print statement in choice 3 of the main function? Oh and the "17 -turn_count" was just part of the requirements of the assignment.
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 was exploring static variable by writing code snippets. I tried below code and it ended up throwing error saying "error: storage class specified for parameter 'b'"
Why static cannot be used in func() ?
Code:
int main() {
int a;
a=5;
func(a);
printf("%d",a);
return 0; }
void func(static int b)
{b=6;
printf("%d",b); }
can i have 1 static variable with instance different value?
View 3 Replies View RelatedIf i declare 2 variables like this static int first, second; will both of them be declared static or will only first be declared static and second a regular variable?
View 5 Replies View Related