C 指针和数组/“sizeof"运算符 [英] C pointers and arrays/ 'sizeof' operator

问题描述

可能的重复:char指针和数组的栈指针区别

为了说明我的问题:

int main(void){
    int myary[20];
    int *myaryPtr;
    myaryPtr = myary;

    sizeof(myary); // Will it return 80? Correct?
    sizeof(myaryPtr); // Will it return 4? Correct?
    return 0;
}

首先，我的假设是否正确?

First off, is my assumption correct?

然后假设我的假设是正确的，详细的解释是什么?我知道我的 20 元素数组是 80 个字节，但是名称 myary 不只是指向数组第一个元素的指针吗?所以不应该也是4吗?

And then assuming my assumption is correct, what is the detailed explanation? I understand that my 20 element array is 80 bytes, but isn't the name myary merely a pointer to the first element of the array? So shouldn't it also be 4?

推荐答案

是的，您的假设是正确的，假设 int 和指针在您的机器上都是 4 个字节长.

Yes, your assumption is correct, assuming an int and a pointer are both 4 bytes long on your machine.

不，数组不是指针.数组名称有时会在某些上下文中衰减为指针，但它们不是一回事.有一个 comp.lang.c 常见问题解答的整个部分专门针对这个共同点混乱.

And no, arrays aren't pointers. The array name sometimes decays into a pointer in certain contexts, but they aren't the same thing. There is a whole section of the comp.lang.c FAQ dedicated to this common point of confusion.

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