c - 问)在这个程序中，sizeof [arr]给出的是数组基地址的地址还是arr的大小？

Question

这个问题已经有答案了:

Why isn't the size of an array parameter the same as within main? (13 个回答)

How to find the size of an array (from a pointer pointing to the first element array)? (17 个回答)

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#include < stdio.h >

void print(int arr[])
{
    int n=sizeof (arr)/sizeof (arr[0]);
    int i;
    for (i=0; i< n; i++)
    {
        printf("%d",arr[i]);
    }
}
int main()
{
    int arr[]={1,2,3,4,5,6};
    print(arr);
}

问)在这个程序中，sizeof [arr]给出的是数组基址的地址还是arr的大小？

Answer 1

sizeof(arr)

将返回 int 指针的大小。您可以做的是计算函数外部数组的大小并将其作为函数参数传递

... 3 Except when it is the operand of the sizeof operator, the _Alignof operator, or the unary & operator, or is a string literal used to initialize an array, an expression that has type ‘‘array of type’’ is converted to an expression with type ‘‘pointer to type’’ that points to the initial element of the array object and is not an lvalue. If the array object has register storage class, the behavior is undefined.

arr 将转换为指向 int 的指针，您将获得该指针的大小。另外需要注意的是，arr 和 &arr 之间存在区别。Arr 的类型为 int*，而 &arr 的类型为 int (*)[10]。