你怎么在C ++中的`realloc`？ [英] How do you `realloc` in C++?

问题描述

如何在C ++中 realloc ？它似乎缺少从语言 - 有新和删除但不是 resize ！

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

我需要它，因为我的程序读取更多的数据，我需要重新分配缓冲区来保存它。我不认为删除旧的指针和新新的，更大的，是正确的选择。

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.

推荐答案

使用:: std :: vector！

Use ::std::vector!

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

成为

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

然后

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

成为

t.resize(n2);

如果要将指针传递到函数，而不是

If you want to pass pointer into function, instead of

Foo(t)

p>

use

Foo(&t[0])

这是绝对正确的C ++代码，因为vector是一个聪明的C数组。

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

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