利用了数组地址相减计算得到数组的元素个数

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>

int my_strlen(char* str)
{
  char* star = str;
  char* end = str;
  while (*end != '\0')
  {
    end++;
  }
  return end - star;

}
int main()
{
  char arr[] = "bit";
  int len = my_strlen(arr);
  printf("%d\n", len);

  

  return 0;
}