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4 Replies Last post: Sep 21, 2012 5:19 PM by Renzo Leiner  
Renzo Leiner Newbie
Renzo Leiner
7 posts since
Sep 21, 2012
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Sep 21, 2012 2:46 PM

Input

Silly question: how can i read from standard input (not arguments line)?

Thx, regards.

Andrey Breslav Apprentice
Andrey Breslav
566 posts since
Jun 11, 2007
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Sep 21, 2012 4:49 PM in response to: Renzo Leiner
Re: Input

readLine():

 

http://jetbrains.github.com/kotlin/versions/snapshot/apidocs/kotlin/io/package-summary.html#readLine()

 

And, of course, System.in is still there for you.

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Renzo Leiner Newbie
Renzo Leiner
7 posts since
Sep 21, 2012
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Sep 21, 2012 5:04 PM in response to: Andrey Breslav
Re: Input

Ok. I've tried with readLine() but i got

 

"C:\Program Files\Java\jdk1.7.0\bin\java" -Didea.launcher.port=7533 -Didea.launcher.bin.path=D:\intellij\bin -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.7.0\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\jce.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\resources.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\rt.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.7.0\jre\lib\ext\zipfs.jar;D:\untitled\out\production\untitled;D:\untitled\lib\kotlin-runtime.jar;D:\intellij\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain namespace

Exception in thread "main" java.lang.IllegalAccessError: tried to access field kotlin.io.namespace.stdin from class kotlin.io.namespace$src$1

at kotlin.io.namespace$src$1.readLine(JIO.kt:144)

at kotlin.io.namespace.readLine(Files.kt)

at namespace.main(a1.kt:2)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:601)

at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

reading further i saw there was a similar issue marked as a bug.... so i was looking for alternatives.
tk u.

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Nikolay Krasko Newbie
Nikolay Krasko
23 posts since
Jun 7, 2010
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Sep 21, 2012 5:01 PM in response to: Renzo Leiner
Re: Input

Kotlin standard library contans println and readLine functions which could help in solving you task gracefully:

 

fun main(args: Array<String>) {
    println("Line: ${readLine()}") // Read line and print it back to console
}

 

In fact under the hood those functions are simple wrappers for java.io, and as kotlin is compatible with Java you can also choose to implement same program like this:

 

import java.io.InputStreamReader
import java.io.BufferedReader
 
fun main(args: Array<String>) {
    val reader = BufferedReader(InputStreamReader(System.`in`))
    System.`out`.println("Line: ${reader.readLine()!!}")
}

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Renzo Leiner Newbie
Renzo Leiner
7 posts since
Sep 21, 2012
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Sep 21, 2012 5:29 PM in response to: Nikolay Krasko
Re: Input

Thx, this way (that is using java.io without wrapping it) has no problems and works fine.

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