EASY/src/easy/ReadNCharactersGivenRead4.java

fishercoder1534 · fishercoder1534 · commit 0d7ec13c9d0e · 2016-09-26T22:18:15.000-07:00
diff --git a/EASY/src/easy/ReadNCharactersGivenRead4.java b/EASY/src/easy/ReadNCharactersGivenRead4.java
@@ -0,0 +1,35 @@
+package easy;
+
+/**
+ * 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.
+ */
+
+/**
+ * The problem description is pretty ambiguous, actually the problem means to Keep reading until
+ * either you have gotten n characters or there is no more characters to read.
+ */
+public class ReadNCharactersGivenRead4 {
+    public int read(char[] buf, int n) {
+        int index = 0, next= 0;
+        char[] buffer = new char[4];
+        while(index < n && (next = read4(buffer)) != 0){
+            for(int i = 0; i < next && index < n; index++, i++){
+                buf[index] = buffer[i];
+            }
+        }
+        return index;
+    }
+
+    private int read4(char[] buffer) {
+        //this is a fake method to make Eclipse happy
+        return 0;
+    }
+}
