标准转换:数组到指针的转换 [英] standard conversions: Array-to-pointer conversion

问题描述

这是 ISO :Standard Conversions:Array-to-pointer conversion: $4.2.1

数组"类型的左值或右值N T"或未知边界的数组T"可以转换为右值类型为指向 T 的指针".结果是指向第一个元素的指针数组.

An lvalue or rvalue of type "array of N T" or "array of unknown bound of T" can be converted to an rvalue of type "pointer to T." The result is a pointer to the first element of the array.

任何人都可以解释这一点，如果可能的话，用一个示例程序.

Can any one explain this, if possible with an example program.

我已经看到这些链接，但我无法理解:

I seen these links already, but i am unable to understand:

数组和右值

我想我可能想出了一个数组类型的右值的例子

推荐答案

在 C 和 C++ 中，数组可以用作指向其第一个元素的指针.实际上，给定一个名为 x 的数组，您可以将 &x[0] 的大部分用法替换为 x.

In both C and C++, an array can be used as if it were a pointer to its first element. Effectively, given an array named x, you can replace most uses of &x[0] with just x.

这是如何与数组对象一起使用下标:

This is how subscripting is able to be used with array objects:

int x[5];
x[2];     // this is the same as (&x[0])[2]

这也是将数组传递给具有指针类型参数的函数的方式:

This is also how an array can be passed to a function that has a parameter of pointer type:

void f(int* p);

int x[5];
f(x);     // this is the same as f(&x[0])

有几种情况不会发生数组到指针的转换.示例包括当数组是 sizeof 或一元-&(地址运算符)的操作数时，当字符串文字用于初始化数组时，以及当数组绑定到对数组的引用时.

There are several contexts in which the array-to-pointer conversion does not take place. Examples include when an array is the operand of sizeof or the unary-& (the address-of operator), when a string literal is used to initialize an array, and when an array is bound to a reference to an array.

这篇关于标准转换:数组到指针的转换的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！