How to new a dynamic array after cin - c++

Question

I'm trying to make a class that contains a pointer, which is the core of a dynamic array.
How to overload the operator >> so I can cin >> to the pointer without know how many characters are going to put?
I was trying:
#include <iostream>
class MyString
{
private:
char* str;
size_t length;
public:
//some code here
friend std::istream& operator>>(std::istream& is, const MyString& other)
{
is >> other.str;
return is;
}
}
and this happened when I try to cin a string:
HEAP CORRUPTION DETECTED
Is there a way to read a string, assign it to my string, and won't use the std::string header?
(I was trying to make a string class that doesn't depend on std::string)

Answer 1

A naive implementation would use is.get() to retrieve one character at a time, and append it to other, resizing if needed. And stop when std::isspace(chr) is true, of course. For that, you need to dynamically allocate memory and keep track of how much space you are using / have available in the implementation of MyString.
Here is the skeleton for that; you probably need to implement the append() method.
friend std::istream& operator>>(std::istream& is, MyString& other) {
while (true) {
int chr = is.get();
if (is.eof() || std::isspace(chr)) {
break;
}
other.append((char)chr);
}
return is;
}

Answer 2

#include <iostream>
#include <string.h>
class MyString
{
private:
size_t length;
char* str;
void getInput(std::istream&is)
{
char c='\0';
while(c!='\n')
{
is.get(c);
length++;
str=(char*)realloc(str, length);
if(c=='\n')
{
str[length-1]='\0';
}
else{
str[length-1]=c;
}
}
}
public:
MyString()
{
length=0;
str=new char[1];
str[0]='\0';
}
//some code here
friend std::istream& operator>>(std::istream& is, MyString& other)
{
std::cout<<"Enter String: ";
other.getInput(is);
return is;
}
void printString()
{
std::cout<<str<<std::endl;
}
~MyString()
{
delete[]str;
length=0;
}
};
int main()
{
MyString s;
std::cin>>s;
s.printString();
}