当使用指向数组的指针时，我们要迭代什么? [英] What do we iterate through when using pointer to an array?

问题描述

这是查找特定字母出现的简单功能.

This is a simple function for finding occurrences of a specific letter.

1:  int count_x(char *p, char a)
2:  {
3:      int count = 0;
4:      while(*p != '\0')
5:      {
6:        if (*p == a)
7:            count++;
8:        p++;
9:      }
10:      return count;
11:  }

我们可以使用p[n]来访问特定元素，或者我们可以取消引用*p并获取该数组的第一个元素作为示例，而我们通常会做所有这些事情.
对我来说奇怪的是位于第8行. 当我们写p++时，我们从一开始就获得了传递-1符号的数组.因此，如果它是hello, world，那么它将是ello, world. 我们正在某种程度上遍历索引，但是我真的不明白如何做.

We can get access to a specific element by using p[n], or we can dereference it *p and get a first element of that array as an example, and all of that stuff we usually do.
The strange thing to me is located at the line number 8. When we write p++, we are getting the array we passed -1 symbol from the beginning. So if it was hello, world then it would be ello, world. We are somehow iterating throuhg the indices but i don't really understand how.

我可以解释所有这些东西如何工作吗?

Can i have an explanation of how all of that stuff works?

推荐答案

循环条件*p != '\0'表示:*迭代直到p指向的值是'\0'.循环体内的语句

The loop condition *p != '\0' means: *iterate until the value pointed by p is '\0'. The statement inside the loop body

p++;

递增指向所传递字符串的下一个字符的指针.

increments the pointer to next character of the string passed.

第一次迭代

+--------+--------+--------+--------+--------+--------+--------+--- ----+--------+--------+--------+--------+
|        |        |        |        |        |        |        |        |        |        |        |        |
|  'h'   |  'e'   |  'l'   |  'l'   |  'o'   |  ','   |  'w'   |  'o'   |  'r'   |  'l'   |  'd'   |  '\0'  |
|        |        |        |        |        |        |        |        |        |        |        |        |
+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+
  ^
  |       
  p   

第二次迭代:

+--------+--------+--------+--------+--------+--------+--------+--- ----+--------+--------+--------+--------+
|        |        |        |        |        |        |        |        |        |        |        |        |
|  'h'   |  'e'   |  'l'   |  'l'   |  'o'   |  ','   |  'w'   |  'o'   |  'r'   |  'l'   |  'd'   |  '\0'  |
|        |        |        |        |        |        |        |        |        |        |        |        |
+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+
             ^
             | 
             p

，依此类推.当p到达点'\0'时，条件*p != '\0'变为false，循环终止. 在每次迭代中，指针p都会更改其指向的位置.字符串保留在其初始存储位置.

and so on. When p comes to point '\0', condition *p != '\0' becomes false and loop terminates. On every iteration it is the pointer p which changes the location where it points. String remain at its initial stored location.

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