new operator - How do you 'realloc' in C++?

Question

How can I realloc in C++? It seems to be missing from the language - there is new and delete but not resize!

I need it because as my program reads more data, I need to reallocate the buffer to hold it. I don't think deleteing the old pointer and newing a new, bigger one, is the right option.

Answer 1

Use ::std::vector!

Type* t = (Type*)malloc(sizeof(Type)*n) 
memset(t, 0, sizeof(Type)*m)

becomes

::std::vector<Type> t(n, 0);

Then

t = (Type*)realloc(t, sizeof(Type) * n2);

becomes

t.resize(n2);

If you want to pass pointer into function, instead of

Foo(t)

use

Foo(&t[0])

It is absolutely correct C++ code, because vector is a smart C-array.