ch4 exercise 4.37 about cpp-primer HOT 7 CLOSED

Hi, @Jtaim Can you paste complete codes?

from cpp-primer.

static_cast from type 'const string* {aka const std::basic_string}' to type 'std::string

From the error message, I can see you want to convert const string * to string. But in exercise 4.37, pv is void*. Thus, following codes work fine:

string str("hello");
const string *ps = &str;
void *pv = const_cast<string*>(ps);
// ...

And, more exact solution is:

pv = static_cast<void*>(const_cast<string*>(ps));

So our answer:

pv = (void*)ps; // pv = const_cast<string*>(ps); or pv = static_cast<void*>(const_cast<string*>(ps));

from cpp-primer.

int main()
{
using std::string;
// rewrite each of the following old-style casts to use a named cast:
// pv = (void_)ps;
// i = int(_pc);
// pv = &d;
// pc = (char*)pv;

int i; double d; const string *ps; char *pc; void *pv;

pv = static_cast<string*>(ps);  // error
pv = static_cast<void*>(const_cast<string*>(ps));
i = static_cast<int>(*pc);
pv = static_cast<void*>(&d);
pc = reinterpret_cast<char*>(pv);
return 0;

}

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i see were i went wrong now. used static_cast instead of const_cast.
well i'm still new at this. :)

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@Jtaim It doesn't matter.

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Hi guys~
If no further discussion needed, please remember to close this issue.
@Jtaim @pezy

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thx @Jtaim

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