debug assertion error(there is a bug in my code)

[Kmilano]

hello
I prepared a following code in visual studio 2017 and when I want to run it in debug state then an error will occurred about debug assertion and I think there is a bug in my code(when I run it with release state I dont have this error and it will run successfully).
also in this line: for (i = 1, x = 0; i < pow(2, r); i = pow(2, x)) I have a warning that "=" the conversion among double to int may loss a data!!

[VictorN]

Did you debug your code?
Where exactly does the "assertion failed" happen?

And FYI: Surviving the Release Version

[Kmilano]

on this line: Data[i] = rand() % 2; when I want to generate random numbers

[2kaud]

on this line: Data[i] = rand() % 2; when I want to generate random numbers

Correct. i becomes out of bounds. Data.size() is the number of elements in the array - not the index value of the last element. So a condition should be < Data.size() for element access. Note that you also have the same issue elsewhere.

Why start at element 1 and not element 0? Elements are accessed from index 0 to index .size() - 1.

PS Note that vector [] doesn't do bounds checking. What happens if [] accesses out of bounds is not defined. For vector bounds checking at run-time there is the .at().

[Kmilano]

when I initialize element from zero the output of my code (special desired calculation among bits) will be wrong
how I can solve this problem in your opinion??

[VictorN]

Your vector Data has the size() of 4. So there 4 elements with the indexes:
Data [0]
Data [1]
Data [2]
Data [3]
But you are trying to access the elements

Data [1]
Data [2]
Data [3]
Data [4] // this is wrong! out of bounds.

BTW, why do you begin array/vector indexing from 1 instead of 0?
It is a serious mistake in C/C++ languages!

[2kaud]

how I can solve this problem in your opinion??

Fix the code!

[2kaud]

for (i = 1; i <= 4; i++)                                                               
	{                                                                                       
		Data.push_back(i);
	}
	for (i = 1; i <= Data.size(); i++)
	{
		Data[i] = rand() % 2;
		std::cout << Data[i] % 2 << " ";
	}

Why all this?? Why not just

for (i = 0; i < 4; ++i)                                                               
    Data.push_back(rand() % 2);

for (const auto& d : Data)
    std::cout << d << " ";

or even

std::vector<int> Data(4);

for (auto& d : Data) {
    d = rand() % 2;
    std::cout << d << " ";
}

[2kaud]

std::vector<int> H(n);
	for (i = 1; i <= n; i++)
	{
		if (i == pow(2, p))
		{
			H[i] = 0;
			p++;
		}
		else
		{
			H[i] = Data[j];
			j++;
		}
	}

try (not tested)

std::vector<int> H(n);
for (i = 1, p =0, j = 0; i <= n; ++i)
    H[i - 1] = (i == (1 << p)) ? ++p, 0 : Data[j++];

[Kmilano]

about your reply in post #9
a warning is for another loop(not the loop that you changed in #9)
in this loop:
for (i = 1, x = 0; i < pow(2, r); i = pow(2, x))

[2kaud]

Why are you using pow with 2? Why not just use << (right shift - don't confuse with << when used as stream insertion!) to multiply by 2 instead?

1 << 1 becomes 2 (pow(2, 1))
1 << 2 becomes 4 (pow(2, 2))
1 << 3 becomes 8 (pow 2, 3)) etc etc

This is quicker than using pow() (although pow may be this as an optimisation?).

So consider

for (i = 1, x = 0; i < (1 << r); i = (1 << x))

[Kmilano]

I applied all points you noticed in your poste, but I dont know why my code will return weird numbers(it must return binary numbers)
my code in post #1 is working in release state in visual studio, but in debug it never works

is it possible try it in visual studio and help me?

[2kaud]

For the code in post #1, where is FinalH defined?

[Kmilano]

excuse me, I wrote a code wrongly in post #1

here, in the following again I attached a correct code:

[2kaud]

The code below compiles OK in both debug and release builds and produces the same output from both builds with the same numbers for Data.

#include <ctime>
#include <vector>
#include <iostream>
using namespace std;

int main()
{
	srand(unsigned(time(0)));
	vector<int> Data (4);

	cout << "a generated numbers are: " << endl;

	for (auto& d : Data)
		cout << (d = rand() % 2) << " ";

	int r = 0;

	for (; (5 + r) > (1 << r); ++r);

	cout << endl << "The no of r : " << r << endl;

	const int n = r + 4;

	std::vector<int> FinalH(n);

	for (int i = 1, p = 0, j = 0; i <= n; ++i)
		FinalH[i - 1] = (i == (1 << p)) ? ++p, 0 : Data[j++];

	cout << endl << "The proper r " << endl;

	for (int i = 1, x = 0; i < (1 << r); ++x, i = (1 << x))
	{
		for (int j = 1; j <= n; ++j)
			if ((i & j) == i)
				FinalH[i - 1] ^= FinalH[j - 1];

		cout << endl << i << " " << FinalH[i - 1];
	}

	cout << endl <<"Total number is: " << n << endl << endl << "the whole codebit: " << endl;

	for (const auto& h : FinalH)
		cout << h << " ";

	cout << endl;
}

If this doesn't display the required results, then at least this will debug!