初始化时是否有必要调用指针= NULL? [英] is it necessary to call pointer = NULL when initializing?

问题描述

当我创建指向某个结构的指针时，是否必须将其设置为NULL，然后分配它然后使用它?为什么?

when I create a pointer to certain struct, do I have to set it to NULL, then alloc it then use it? and why?

推荐答案

否，声明语言时，没有要求(就语言而言)初始化任何指针变量.因此

No, there is no requirement (as far as the language is concerned) to initialize a pointer variable to anything when declaring it. Thus

T* ptr;

是有效的声明，它引入了具有不确定值的名为ptr的变量.您甚至可以以某种方式使用该变量，而无需先分配任何内容或将其设置为任何特定值:

is a valid declaration that introduces a variable named ptr with an indeterminate value. You can even use the variable in certain ways without first allocating anything or setting it to any specific value:

func(&ptr);

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