The API: int read4(char *buf) reads 4 characters at a time from a file.
The return value is the actual number of characters read. For example, it returns 3 if there is only 3 characters left in the file.
By using the read4 API, implement the function int read(char *buf, int n) that reads n characters from the file.
Note:The read function will only be called once for each test case.
注意：It assumes only read less than n chars, even if the there are more than n chars in a file.
public int read(char[] buf, int n) { boolean eof = false; // end of file flag int total = 0; // total bytes have read char[] tmp = new char[4]; // temp buffer while (!eof && total < n) { int count = read4(tmp); // check if it's the end of the file eof = count < 4; // get the actual count count = Math.min(count, n - total); // copy from temp buffer to buf for (int i = 0; i < count; i++) buf[total++] = tmp[i]; } return total; }
reference：https://discuss.leetcode.com/category/166/read-n-characters-given-read4
转载于:https://www.cnblogs.com/hygeia/p/5702953.html
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