[C++]重新定义 y 值的基本数组代码。它正在工作，但无法解释为什么

我在网络上看到了一些代码，并试图弄清楚它是如何工作的。我试图在每行上留下评论，但我不明白y [0]为5555。我猜y [0]可能会更改为数字[0]，但是为什么呢？x值仍然是1。嗯..这是因为y[0] = 1;没有int数据类型？

#include 使用名称空间std;

void m(int, int []);
/*this code explains a variable m that m consists of two parts, int and int array*/
int main()
{
  int x = 1; /* x value is declared to 1*/
  int y[10]; /*Array y[10] is declared but value is not given*/
  y[0] = 1; /*Array y's first value is declared to 1 but data type is not given*/

  m(x, y); /*This invokes m with x and y*/
  cout << "x is " << x << endl; 
  cout << "y[0] is " << y[0] << endl;
  return 0;
}
void m(int number, int numbers[]) /*variable names in m are given, number and numbers.*/
{
  number = 1001; /*number has int 1001 value*/
  numbers[0] = 5555; /*This overrides y to numbers[], so y[0] =1 changes to numbers[0] = 5555.*/
}
/*This program displays 
 * x is 1
 * y[0] is 5005
 * y[0] value has changed but x has not.
 * */