pointer addresses--help.

[codekiddy]

hello,
I'm exercising on to how manipulate with pointer addresses,
this piece of code work's fine and it show's the values when exiting function named "f", but I get an error at the end... that error line is commented.

#include <iostream>
using namespace std;
void f(char**, int**);

int main() {
	char* pass = nullptr;
	int* net = nullptr;
	f(&pass, &net);
	cout << pass << endl << *net;
	delete[] pass; //error is here (no error if comment this line out!!)
	delete net;
	return 0;
}
void f(char** x, int** y) {
	char* a = new char[10];
	int* b  = new int(99);
	a = "test";
	*x = a;
	*y = b;
}

here is output:

debug assertion failed!
BLOCK_TYPE_IS_VALID(pHead->nBlockUse)

as I said...
if line 10 is commented out no error at all,
but memory leak is a payload then lol.
please help.

[ciphermagi]

delete pass;

[shacktar]

This is not how you assign a char*

a = "test";

Try using the strcpy function defined in the <cstring> header. You may have access to strcpy simply by including iostream.

[codekiddy]

@ciphermagi
I've try that but no success :/

@shacktar

#include <iostream>
using namespace std;
void f(char**, int**);

int main() {
	char* pass = nullptr;
	int* net = nullptr;
	f(&pass, &net);
	cout << pass << endl << *net << endl;
	delete[] pass;
	delete net;
	system("pause");
	return 0;
}
void f(char** x, int** y) {
	char* a = new char[10];
	int* b  = new int(99);
	//a = "test";
	*x = a;
	*y = b;
}

now as it is here work's ...
what if I don't wanna use any of standard functions?
I mean how to initialize it just like that?
maybe using some for loop... I'll try that...

[ciphermagi]

You can't just stuff chars into a, you have to put them into the address of a.

[codekiddy]

void f(char** x, int** y) {
	char* a = new char[10];
	int* b  = new int(99);
	cout << "input data: ";
	cin >> a;   //option 1
	strcpy(a, "test");  //option  2
	*x = a;
	*y = b;
}

I think you can't pass values into address of a pointer !?
or how do u mean into address of a?

[ciphermagi]

a is a pointer. You can't put values into a pointer, it doesn't make sense. You have to put values into the memory that's pointed.

[Caligulaminus]

#include <iostream>
using namespace std;
void f(char**, int**);

int main() {
	char* pass = nullptr;
	int* net = nullptr;
	f(&pass, &net); // see comments in f()
	cout << pass << endl << *net;
	delete[] pass; // you cannot delete pass since it now points to "test" which
                       // you did not allocate on the heap.
                       // the new char[10]; below is a memory leak
	delete net;
	return 0;
}
void f(char** x, int** y) { // x points to pass
	char* a = new char[10];
	int* b  = new int(99);
	a = "test";
	*x = a; // now pass points to "test"
	*y = b;
}

Edit: clarified (hopefully)

[ceruleus]

no I still think you've got issues here... when you say a = "test"; what do you think that is doing?

[youtubezou]

char* a = new char[10]; //a point to the memory that allocated by new.
a = "test"; //now,a is changed, a point to a string constant.
//and the memory that allocated by new was dropped.

delete[] pass; //because pass are equal to a,so you are trying to release a string constant memory.That's why the program fail.