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_Flaviu wrote: I really don't know hot to overcome this
The javascript and/or webassembly needs to execute. Websites are not flat files anymore.
You will need to use a complete browser engine to parse the DOM. In other words most websites today are generating dynamic content via javascript. You need to think outside the box here... that javascript you see needs to execute in order to generate the page.
One quick way to do this would be using a hidden Internet Explorer window as the backend. Creating a Web Browser-Style MFC Application[^]. You could set the CHtmlView to load the site and dump the top document after javascript has modified the DOM.
Some of my tools are using a custom webkit[^] as the backend to do this. You can also use Chromium Embedded[^]. You could probably spend less than a day modifying cefsimple[^] to load the website and dump the top document to file after javascript has executed.
Good Luck.
Best Wishes,
-David Delaune
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I've always wondered this -why can't you declare variables after a case label in a switch statement? In C++ you can declare variables pretty much anywhere (and declaring them close to first use is obviously a good thing) but the following still won't work
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You can, you just need to put them, and the code that uses them inside curly braces, thus:
switch (number)
{
case 1:
{
int i; }
}
Variables not inside such a block are considered to have the scope of the entire switch block. But if they are declared in a single case statement there is a possibility that they would not get initialised safely. To make a variable available to multiple case statements it must be declared before the switch.
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in the below program it i have used both ways i.e. passed arguments by reference and pointers.
1. Arguments by reference:
#include <iostream>
using namespace std;
template<class T>
void swap(T &x, T &y){
T temp = x;
x = y;
y = temp;
}
void fun(int m, int n, float a, float b){
cout << "m & n before swap: " << m << " " << n << endl;
swap(m, n);
cout << "m & n after swap: " << m << " " << n << endl;
cout << "i & j before swap: " << a << " " << b << endl;
swap(a, b);
cout << "i & j after swap: " << a << " " << b << endl;
}
int main(){
fun(100, 200, 11.22, 33.44);
return 0;
}
2. Arguments by pointers:
#include <iostream>
using namespace std;
template<class T>
void swap(T *x, T *y){
T temp = x;
x = y;
y = temp;
}
void fun(int m, int n, float a, float b){
cout << "m & n before swap: " << m << " " << n << endl;
swap(m, n);
cout << "m & n after swap: " << m << " " << n << endl;
cout << "i & j before swap: " << a << " " << b << endl;
swap(a, b);
cout << "i & j after swap: " << a << " " << b << endl;
}
int main(){
fun(100, 200, 11.22, 33.44);
return 0;
}
also if i pass the arguments by reference but make it a constant then also i works, why ?
#include <iostream>
using namespace std;
template<class T>
void swap(const T &x, const T &y){
T temp = x;
x = y;
y = temp;
}
void fun(int m, int n, float a, float b){
cout << "m & n before swap: " << m << " " << n << endl;
swap(m, n);
cout << "m & n after swap: " << m << " " << n << endl;
cout << "i & j before swap: " << a << " " << b << endl;
swap(a, b);
cout << "i & j after swap: " << a << " " << b << endl;
}
int main(){
fun(100, 200, 11.22, 33.44);
return 0;
}
Thank you.
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You have a name clash with std::swap. Try
#include <iostream>
using std::cout;
using std::endl;
template<class T>
void swap(T &x, T &y){
T temp = x;
x = y;
y = temp;
}
void fun(int m, int n, float a, float b){
cout << "m & n before swap: " << m << " " << n << endl;
swap(m, n);
cout << "m & n after swap: " << m << " " << n << endl;
cout << "i & j before swap: " << a << " " << b << endl;
swap(a, b);
cout << "i & j after swap: " << a << " " << b << endl;
}
int main()
{
fun(100, 200, 11.22, 33.44);
}
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here in the below program i have tried to pass the values of 1d matrix to the object of class Vector by using constructor explicit call.
#include <iostream>
using namespace std;
const int size = 3;
class Vector {
int *v;
public:
Vector(){
v = new int[size];
for(int i=0; i<size; i++)
v[i] = 0;
}
Vector(int *a){
for(int i=0; i<size; i++){
v[i] = a[i] ;
}
}
int operator * (Vector &y){
int sum=0;
for(int i=0; i<size; i++)
sum += this->v[i] * y.v[i] ;
return sum;
}
void display(){
for(int i=0; i<size; i++)
cout << v[i] << " ";
cout << endl;
}
};
int main(){
int x[3] = {1, 2, 3};
int y[3] = {6, 3, 9};
Vector v1, v2;
v1 = y;
v2 = x;
cout << "v1 = ";
v1.display();
cout << "v2 = ";
v2.display();
cout << "v1 x v2 = " << v1 * v2 << endl ;
return 0;
}
Quote: cout << "v1 = ";
v1.display();
cout << "v2 = ";
v2.display();
the above portion of code doesn't works as expected it gives,
Output:
Quote:
6 3 9
6 3 9
v1 = 6 3 9
v2 = 6 3 9
v1 x v2 = 126
Expected:
Quote: Quote:
1 2 3
6 3 9
v1 = 1 2 3
v2 = 6 3 9
v1 x v2 = 39
Thank you
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The program shouldn't run as is. In your second constructor, you aren't allocating the memory for the vector. (You also aren't deleting that memory in a destructor.)
Also note that you construct the v object in the default constructor. Since there is no assignment operator AND the second constructor is not marked explicit, it is creating a second instance of Vector and then member-wise copying that to the first, clobbering the allocation of v in the first instance. (Why your compiler is letting you get away with this is a mystery to me.)
So, add a destructor and then put "explicit" in front of the second constructor.
Then, remove the assignments and replace the declaration line with: v1(x), v2(y).
(It's still messy code, but in a debugger, you can now see how you are explicitly calling the second constructor and never the first.)
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Since you know at compile time the array size, why don't you allocate it on the stack?
#include <iostream>
#include <array>
using namespace std;
constexpr size_t SIZE = 3;
class Vector
{
array<int,SIZE> x{};
public:
Vector (const array<int,SIZE> & a)
{
for (size_t n=0; n<SIZE; ++n)
x[n] = a[n];
}
int operator * (const Vector & v) const
{
int result = 0;
for (size_t n=0; n<SIZE; ++n)
result += x[n] * v.x[n];
return result;
}
friend ostream & operator << ( ostream & os, const Vector & v);
};
ostream & operator << ( ostream & os, const Vector & v)
{
for (const auto & i : v.x)
os << i << " ";
return os;
}
int main()
{
array<int, SIZE> x{1,2,3};
array<int, SIZE> y{6,3,9};
Vector v1{x};
Vector v2{y};
cout << "v1 " << v1 << endl;
cout << "v2 " << v2 << endl;
cout << "v1*v2 = " << (v1*v2) << endl;
}
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I'm converting a project from VS2005 to VS2017 and have many errors:
I'm getting many errors for items not being members of System
Windows
Forms
Drawing
Panel
Button
etc....
Is there something missing from my old code or is this not available in VS2017 or is there something that wasn't included?
I think the app creates a form....
Any help to debug would be much appreciated.
Jim
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Is it a managed C++ project type?
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Then it would be better to post in the Managed C++/CLI Forum.
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This is silly , but most I/O devices spec sheets data are written as "hex".
If I want to pass this
char *TXBuffer = (char*) 0x04;
to a function it has to be type casted.
Like so
<pre lang="c++">
char *TXBuffer = (char*) 0x04;
int *TEST = (int*)0x04;</pre>
If not I'll get "invalid conversion".
Cheers
Vaclav
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Vaclav_ wrote: char *TXBuffer = (char*) 0x04;
No you don't need to do that, and you shouldn't because it is wrong. You are trying to pass the value 0x04 as the buffer address, which will cause an access violation.
If you need a buffer containing the hex value, and you want to send that buffer's address to a function then you need to do one or other of the following:
unsigned char TXBuffer = 0x04; function(&TXBuffer);
unsigned char TXBuffer[] = { 0x04, 0 }; function(TXBuffer);
xxx function(unsigned char* buffer)
{
unsigned char value = *buffer; buffer++; value = *buffer; }
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Thanks Richard, you are a pal.
Appreciate your comments.
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Hi, I wrote a small c program on a microcontroller, 32bit.
I met a weird problem.
I wrote code like:
const char strtest[] = "Test123\r\n"; UART_print(strtest);
the output is fine, I can see the output on Teraterm(RS232 interface tool), like:
Test123
Test123
..
But when I try code:
char str123[] = "Test123\r\n";
UART_print(strtest);
The output is only the first element:
TTTTTTTT
Any hint is appreciated.
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focusdoit wrote: char str123[] = "Test123\r\n";
UART_print(strtest);
Where is str123 used?
What is the signature of UART_print()?
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles
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Please show the code for the UART_print function.
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focusdoit wrote: But when I try code:
char str123[] = "Test123\r\n";
UART_print(strtest);
You defined the variable str123 but you print the strtest. Where and how is this strtest defined?
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It's memory allocation problem. the MCU has 2 cpu inside, and one set of peripheral units, compiler put str123 in DMA Access prohibited area.
Embedded programming, too many tricks.
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I like to rebuild my Raspberry Pi code to have "top down" structure.
On top would be the device "primitives" class - for example LCD draw circle
In middle I like to have hardware specifics, maybe even protocol (SPI,I2C) specifics - BCMx processor
And finally the access to I/O "pins"
I was thinking of "cascaded C++ " hierarchy but it would not be C++ hierarchy for real.
Or just simple top class having supporting class as variable. Not sure how flexible that would be.
The idea is to be able to add another "top" device and reuse the supporting classes.
I hope this makes sense and if I have asked this before - just ignore OF.
Thanks
Cheers Vaclav
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It actually more complex than that because on a Pi2,Pi3 you have 4 cores so you will have spinlocks/semaphores on all the devices.
What are you doing with cores 1,2,3 at the moment are they still parked or in use?
I assume your code isn't under linux given you have dragged the devices out to objects
Assuming baremetal I would strongly suggest you look at circle
GitHub - rsta2/circle: A C++ bare metal environment for Raspberry Pi with USB[^]
I am not sure you can develop much of a hierarchy it all needs to be fairly flat if you want to use the multicores, welcome to multicore programming
In vino veritas
modified 9-May-18 11:28am.
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