THE PACKAGE JAVA.IO

java.io.StreamTokenizer

22.14

Here is a simple example of the use of a

StreamTokenizer

. The following

code merely reads all the tokens in the standard input stream and prints an identi 

fication of each one. Changes in the line number are also noted.

import java.io.StreamTokenizer;

import java.io.IOException;

class Tok {

public static void main(String[] args) {

StreamTokenizer st = new StreamTokenizer(System.in);

st.ordinaryChar( / );

int lineNum =  1;

try {

for (int tokenType = st.nextToken();

tokenType != StreamTokenizer.TT_EOF;

tokenType = st.nextToken()) {

int newLineNum = st.lineno();

if (newLineNum != lineNum) {

System.out.println("[line " + newLineNum

+ "]");

lineNum = newLineNum;

}

switch(tokenType) {

case StreamTokenizer.TT_NUMBER:

System.out.println("the number " + st.nval);

break;

case StreamTokenizer.TT_WORD:

System.out.println("identifier " + st.sval);

break;

default:

System.out.println("  operator "

+ (char)tokenType);

}

}

} catch (IOException e) {

System.out.println("I/O failure");

}

}

}

If the input stream contains this data:

10 LET A = 4.5

20 LET B = A*A

30 PRINT A, B

then the resulting output is:

[line 1]

the number 10.0

identifier LET

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