LeetCode – Refresh – Read N Characters Given Read4

 1 // Forward declaration of the read4 API.
 2 int read4(char *buf);
 3 
 4 class Solution {
 5 public:
 6     /**
 7      * @param buf Destination buffer
 8      * @param n   Maximum number of characters to read
 9      * @return    The number of characters read
10      */
11     int read(char *buf, int n) {
12         int len = 0, each = INT_MAX;
13         while (len < n && (each = read4(buf))) {
14             len += each;
15             buf += each;
16         }
17         if (len >= n) {
18             buf[n-len] = ‘\0‘;
19             len = n;
20         }
21         return len;
22     }
23 };