数组作为函数的形参

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当一个数组名作为函数参数时，数组名的值就是指向数组第一个元素的指针，所以此时传递给函数的是一个地址。

#include <iostream>
#include <stdlib.h>
#include <string.h>
using namespace std;

void func(char str[100]);

int main()
{
    char str[] = "hello";
    char *p = str;
    int n = 10;
    cout << "0: " << strlen(str) << endl;; //此处的str指存储在数组中的字符串
    cout << "1: " << sizeof(str) << endl;; //此处的str指数组
    cout << "2: " << sizeof(p) << "\n"; //此处的p是指针
    cout << "3: " << sizeof(n) << '\n'; //此处的n是int整型数据
    cout << endl; 

    char array[100] = {};
    func(array);

    return 0;
}

void func(char str[100])
{
    cout << "4: " << sizeof(str) << '\n'; //此处的str是地址
    char array[100] = {0};
    cout << "5: " << sizeof(array) << '\n'; //此处的array是数组
    void *p = malloc(100);
    cout << "6: " << sizeof(p) << '\n'; //此处的p是指针
}

运行结果： 

 

#include <iostream>
using namespace std;

int main()
{
    int a[10] = {123, 456};
    int *p;
    cout << "1: " << *a << "\n"; //此处对a数组名解引用时，a代表首个元素的地址
    cout << "2: " << *(a+1) << "\n"; //此处对a数组名进行加减运算时，a代表元素地址
    cout << "3: " << *p << "\n"; //此处的p是一个声明但未初始化的指针
    cout << "4: " << sizeof(a) << "\n"; //此处的a是数组名
    cout << "5: " << sizeof(p) << "\n"; //此处的p是指针

    return 0;
}

运行结果：