Reading an int using Buffered Reader

Question

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("please enter the size of array");
size = br.read();
sarray = new int[size];

for (int i = 0; i < size; i++) {
    sarray[i] = i;
}
System.out.println(sarray.length);

When I tried to print the length of the array, it is showing as "51" even though i gave the size as "3".

Answer 1

Use readLine() method instead of read() method .

int size = Integer.parseInt(br.readLine());

read() method doesnt return the exact int value of input.

public int read() throws IOException Reads a single character. Overrides: read in class Reader Returns: The character read, as an integer in the range 0 to 65535 (0x00-0xffff), or -1 if the end of the stream has been reached Throws: IOException - If an I/O error occurse

Ref : http://docs.oracle.com/javase/7/docs/api/java/io/BufferedReader.html#read()

Answer 2

BufferedReader.read() reads a single character and returns it as an integer (ie returns the ASCII code of the character).

When you input 3 to your BufferedReader , read() will read it as a character, ie as '3' , which corresponds to the ASCII code 51.

You can verify this by executing the following code:

System.out.println((int) '3'); // prints 51