strcopy problems

[binso]

hi.
I am writing a program to copy a string without using the strcopy funcion.
I am copying from a to b, but I am not able to delete from b to be ready for another input.
I have tried numerous ways, both with for loop and delete []b but nothing seems to work.

  #include <iostream>
using namespace std;

char strcpy2 (char* b, char* a);

int main()
{
    char a[1000], b[1000];
    while (cin.getline(a, 1000))
    {
        cout << "strcpy2(b, \"" << a << "\");" << endl;
        strcpy2(b, a);
        cout << "b = \"" << b << "\";" << endl;
    }

    return 0;
}

char strcpy2 (char* b, char* a)
{


    for (int i = 0 ; i < *a ; i++)
    {
        b[i] = a[i];
    }
    delete b;
    b = NULL;





return 0;


}

[ne555]

A copy operation that kills the source object would not be a copy.

> but I am not able to delete from b to be ready for another input.
You do not need to do anything prior to a reading.
If you do want for b to be considered "empty" then you could simply b[0] = '\0';

Only delete what you new
Only delete[] what you new[]

Also, it is obvious that line 28 has no effect, as it is modifying a pointer local to the function.

[mobotus]

const int SIZE = 1000;

void strcpy2(char a[], char b[], const int SIZE){

	for (int i = 0; i < SIZE; i++)
		b[i] = a[i];
}

Arrays are default pass by reference because array names are just pointers anyway no need to get fancy. Just pass and copy if you want.

[binso]

Thanks, used mobutus solution and it worked.

If however i would have used it like I started to how would would that be presented and how to get the null-terminated copied over as well. It seems that was my problem.

[mobotus]

This maybe what you are thinking about.

#include <iostream>

using namespace std;

const int SIZE = 3;

char *strcpy2(const char * a, const int SIZE){

	char *b = new char[SIZE];
	for (int i = 0; i < SIZE; i++)
		b[i] = a[i];
	return b;

}

int main(){

	char a[] = { 'A', 'B', 'C' };
	char *ptr = strcpy2(a, SIZE);
	for (int i = 0; i < SIZE; i++)
		cout << ptr[i];
	delete[] ptr;

	return 0;
}