拾遗：不用使 sizeof 获取数组大小

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#include <stdio.h>
#include <unistd.h>

int
main(void) {
    int A[256] = {0};
    size_t num = (int *)(&A + 1) - (int *)&A;
    size_t len = (char *)(&A + 1) - (char *)&A;
    printf("数组元素个数是 %zd\n字节总长度是 %zd\n", num, len);
    return 0;
}

[fh@dell Trash]$ ./a.out 
数组元素个数是 256
字节总长度是 1024

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