c - 堆栈段中意外的内存分配

Question

我试图看到对于给定的函数，内存堆栈段上的内存分配将以连续的方式发生。因此，我编写了以下代码并得到了以下输出。

对于int分配 我看到内存地址按预期出现，但不是字符数组。内存地址0xbff1599c之后我期待下一个地址是 0xbff159a0而不是0xbff159a3 。另外，从char开始是 1 个字节，而我使用的是 4 个字节，所以在 0xbff159a3 之后我在期待0xbff159a7而不是0xbff159a8

如果我删除字符部分，所有内存位置都会按预期出现，但我无法使用字符数组获取预期的内存位置。

我的基本假设是，在堆栈段上，内存始终是连续的。我希望这没有错。

#include <stdio.h>

int main(void)
{
    int x = 10;
    printf("Value of x is %d\n", x);
    printf("Address of x is %p\n", &x);
    printf("Dereferencing address of x gives %d\n", *(&x));
    printf("\n");

    int y = 20;
    printf("Value of y is %d\n", y);
    printf("Address of y is %p\n", &y);
    printf("Dereferencing address of y gives %d\n", *(&y));
    printf("\n");

    char str[] = "abcd";
    printf("Value of str is %s\n", str);
    printf("Address of str is %p\n", &str);
    printf("Dereferencing address of str gives %s\n", *(&str));
    printf("\n");

    int z = 30;
    printf("Value of z is %d\n", z);
    printf("Address of z is %p\n", &z);
    printf("Dereferencing address of z gives %d\n", *(&z));
}

输出:

Value of x is 10
Address of x is 0xbff159ac
Dereferencing address of x gives 10

Value of y is 20
Address of y is 0xbff159a8
Dereferencing address of y gives 20

Value of str is abcd
Address of str is 0xbff159a3
Dereferencing address of str gives abcd

Value of z is 30
Address of z is 0xbff1599c
Dereferencing address of z gives 30

Answer 1

Also, since char is 1 byte and I am using 4 bytes, so after 0xbff159a3 I was expecting 0xbff159a7 and not 0xbff159a8

char 占用 1 个字节，但 str 是字符串，您没有计算 '\0'它位于字符串的末尾，因此，char str[]="abcd" 占用 5 字节。