C/C++ Char Pointer Crash

Question

Let\'s say that a function which returns a fixed ‘random text’ string is written like

char *Function1()
{ 
return “Some text”;
}

then the p

Answer 1

You are trying to modify a string literal. According to the Standard, this evokes undefined behavior. Another thing to keep in mind (related) is that string literals are always of type const char*. There is a special dispensation to convert a pointer to a string literal to char*, taking away the const qualifier, but the underlying string is still const. So by doing what you are doing, you are trying to modify a const. This also evokes undefined behavior, and is akin to trying to do this:

const char* val = "hello";
char* modifyable_val = const_cast(val);
modifyable_val[1] = 'n';  // this evokes UB

Instead of returning a const char* from your function, return a string by value. This will construct a new string based on the string literal, and the calling code can do whatever it wants:

#include 

std::string Function1()
{ 
return “Some text”;
}

...later:

std::string s = Function1();
s[1] = 'a';

Now, if you are trying to change the value that Function() reuturns, then you'll have to do something else. I'd use a class:

#include 
class MyGizmo
{
public: 
  std::string str_;
  MyGizmo() : str_("Some text") {};
};

int main()
{
  MyGizmo gizmo;
  gizmo.str_[1] = 'n';
}