Kotlin - ISBN Verifier Done
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Anthony Cicchetti
parent
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53d3bf9794
9 changed files with 472 additions and 0 deletions
50
kotlin/isbn-verifier/README.md
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50
kotlin/isbn-verifier/README.md
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# ISBN Verifier
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The [ISBN-10 verification process](https://en.wikipedia.org/wiki/International_Standard_Book_Number) is used to validate book identification
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numbers. These normally contain dashes and look like: `3-598-21508-8`
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## ISBN
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The ISBN-10 format is 9 digits (0 to 9) plus one check character (either a digit or an X only). In the case the check character is an X, this represents the value '10'. These may be communicated with or without hyphens, and can be checked for their validity by the following formula:
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```
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(x1 * 10 + x2 * 9 + x3 * 8 + x4 * 7 + x5 * 6 + x6 * 5 + x7 * 4 + x8 * 3 + x9 * 2 + x10 * 1) mod 11 == 0
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```
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If the result is 0, then it is a valid ISBN-10, otherwise it is invalid.
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## Example
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Let's take the ISBN-10 `3-598-21508-8`. We plug it in to the formula, and get:
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```
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(3 * 10 + 5 * 9 + 9 * 8 + 8 * 7 + 2 * 6 + 1 * 5 + 5 * 4 + 0 * 3 + 8 * 2 + 8 * 1) mod 11 == 0
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```
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Since the result is 0, this proves that our ISBN is valid.
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## Task
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Given a string the program should check if the provided string is a valid ISBN-10.
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Putting this into place requires some thinking about preprocessing/parsing of the string prior to calculating the check digit for the ISBN.
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The program should be able to verify ISBN-10 both with and without separating dashes.
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## Caveats
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Converting from strings to numbers can be tricky in certain languages.
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Now, it's even trickier since the check digit of an ISBN-10 may be 'X' (representing '10'). For instance `3-598-21507-X` is a valid ISBN-10.
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## Bonus tasks
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* Generate a valid ISBN-13 from the input ISBN-10 (and maybe verify it again with a derived verifier).
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* Generate valid ISBN, maybe even from a given starting ISBN.
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## Source
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Converting a string into a number and some basic processing utilizing a relatable real world example. [https://en.wikipedia.org/wiki/International_Standard_Book_Number#ISBN-10_check_digit_calculation](https://en.wikipedia.org/wiki/International_Standard_Book_Number#ISBN-10_check_digit_calculation)
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## Submitting Incomplete Solutions
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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28
kotlin/isbn-verifier/build.gradle
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28
kotlin/isbn-verifier/build.gradle
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buildscript {
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ext.kotlin_version = '1.2.40'
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repositories {
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mavenCentral()
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}
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dependencies {
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classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
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}
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}
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apply plugin: 'kotlin'
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repositories {
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mavenCentral()
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}
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dependencies {
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compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
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testCompile 'junit:junit:4.12'
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testCompile "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"
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}
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test {
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testLogging {
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exceptionFormat = 'full'
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events = ["passed", "failed", "skipped"]
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}
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}
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5
kotlin/isbn-verifier/gradle/wrapper/gradle-wrapper.properties
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5
kotlin/isbn-verifier/gradle/wrapper/gradle-wrapper.properties
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distributionBase=GRADLE_USER_HOME
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distributionPath=wrapper/dists
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distributionUrl=https\://services.gradle.org/distributions/gradle-4.10-bin.zip
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zipStoreBase=GRADLE_USER_HOME
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zipStorePath=wrapper/dists
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172
kotlin/isbn-verifier/gradlew
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172
kotlin/isbn-verifier/gradlew
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#!/usr/bin/env sh
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##############################################################################
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##
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## Gradle start up script for UN*X
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##
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##############################################################################
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# Attempt to set APP_HOME
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# Resolve links: $0 may be a link
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PRG="$0"
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# Need this for relative symlinks.
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while [ -h "$PRG" ] ; do
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ls=`ls -ld "$PRG"`
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link=`expr "$ls" : '.*-> \(.*\)$'`
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if expr "$link" : '/.*' > /dev/null; then
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PRG="$link"
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else
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PRG=`dirname "$PRG"`"/$link"
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fi
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done
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SAVED="`pwd`"
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cd "`dirname \"$PRG\"`/" >/dev/null
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APP_HOME="`pwd -P`"
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cd "$SAVED" >/dev/null
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APP_NAME="Gradle"
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APP_BASE_NAME=`basename "$0"`
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# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
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DEFAULT_JVM_OPTS=""
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# Use the maximum available, or set MAX_FD != -1 to use that value.
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MAX_FD="maximum"
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warn () {
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echo "$*"
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}
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die () {
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echo
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echo "$*"
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echo
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exit 1
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}
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# OS specific support (must be 'true' or 'false').
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cygwin=false
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msys=false
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darwin=false
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nonstop=false
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case "`uname`" in
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CYGWIN* )
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cygwin=true
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;;
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Darwin* )
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darwin=true
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;;
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MINGW* )
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msys=true
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;;
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NONSTOP* )
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nonstop=true
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;;
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esac
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CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
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# Determine the Java command to use to start the JVM.
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if [ -n "$JAVA_HOME" ] ; then
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if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
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# IBM's JDK on AIX uses strange locations for the executables
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JAVACMD="$JAVA_HOME/jre/sh/java"
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else
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JAVACMD="$JAVA_HOME/bin/java"
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fi
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if [ ! -x "$JAVACMD" ] ; then
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die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
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Please set the JAVA_HOME variable in your environment to match the
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location of your Java installation."
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fi
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else
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JAVACMD="java"
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which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
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Please set the JAVA_HOME variable in your environment to match the
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location of your Java installation."
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fi
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# Increase the maximum file descriptors if we can.
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if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
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MAX_FD_LIMIT=`ulimit -H -n`
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if [ $? -eq 0 ] ; then
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if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
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MAX_FD="$MAX_FD_LIMIT"
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fi
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ulimit -n $MAX_FD
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if [ $? -ne 0 ] ; then
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warn "Could not set maximum file descriptor limit: $MAX_FD"
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fi
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else
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warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
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fi
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fi
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# For Darwin, add options to specify how the application appears in the dock
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if $darwin; then
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GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
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fi
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# For Cygwin, switch paths to Windows format before running java
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if $cygwin ; then
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APP_HOME=`cygpath --path --mixed "$APP_HOME"`
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CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
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JAVACMD=`cygpath --unix "$JAVACMD"`
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# We build the pattern for arguments to be converted via cygpath
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ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
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SEP=""
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for dir in $ROOTDIRSRAW ; do
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ROOTDIRS="$ROOTDIRS$SEP$dir"
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SEP="|"
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done
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OURCYGPATTERN="(^($ROOTDIRS))"
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# Add a user-defined pattern to the cygpath arguments
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if [ "$GRADLE_CYGPATTERN" != "" ] ; then
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OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
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fi
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# Now convert the arguments - kludge to limit ourselves to /bin/sh
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i=0
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for arg in "$@" ; do
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CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
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CHECK2=`echo "$arg"|egrep -c "^-"` ### Determine if an option
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if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then ### Added a condition
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eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
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else
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eval `echo args$i`="\"$arg\""
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fi
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i=$((i+1))
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done
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case $i in
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(0) set -- ;;
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(1) set -- "$args0" ;;
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(2) set -- "$args0" "$args1" ;;
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(3) set -- "$args0" "$args1" "$args2" ;;
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(4) set -- "$args0" "$args1" "$args2" "$args3" ;;
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(5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
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(6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
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(7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
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(8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
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(9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
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esac
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fi
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# Escape application args
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save () {
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for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
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echo " "
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}
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APP_ARGS=$(save "$@")
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# Collect all arguments for the java command, following the shell quoting and substitution rules
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eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
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# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
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if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
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cd "$(dirname "$0")"
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fi
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exec "$JAVACMD" "$@"
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84
kotlin/isbn-verifier/gradlew.bat
vendored
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84
kotlin/isbn-verifier/gradlew.bat
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@if "%DEBUG%" == "" @echo off
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@rem ##########################################################################
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@rem
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@rem Gradle startup script for Windows
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@rem
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@rem ##########################################################################
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@rem Set local scope for the variables with windows NT shell
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if "%OS%"=="Windows_NT" setlocal
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set DIRNAME=%~dp0
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if "%DIRNAME%" == "" set DIRNAME=.
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set APP_BASE_NAME=%~n0
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set APP_HOME=%DIRNAME%
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@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
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set DEFAULT_JVM_OPTS=
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@rem Find java.exe
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if defined JAVA_HOME goto findJavaFromJavaHome
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set JAVA_EXE=java.exe
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%JAVA_EXE% -version >NUL 2>&1
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if "%ERRORLEVEL%" == "0" goto init
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echo.
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echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
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echo.
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echo Please set the JAVA_HOME variable in your environment to match the
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echo location of your Java installation.
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goto fail
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:findJavaFromJavaHome
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set JAVA_HOME=%JAVA_HOME:"=%
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set JAVA_EXE=%JAVA_HOME%/bin/java.exe
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if exist "%JAVA_EXE%" goto init
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echo.
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echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
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echo.
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echo Please set the JAVA_HOME variable in your environment to match the
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echo location of your Java installation.
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goto fail
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:init
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@rem Get command-line arguments, handling Windows variants
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if not "%OS%" == "Windows_NT" goto win9xME_args
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:win9xME_args
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@rem Slurp the command line arguments.
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set CMD_LINE_ARGS=
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set _SKIP=2
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:win9xME_args_slurp
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if "x%~1" == "x" goto execute
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set CMD_LINE_ARGS=%*
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:execute
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@rem Setup the command line
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set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
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@rem Execute Gradle
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"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
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:end
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@rem End local scope for the variables with windows NT shell
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if "%ERRORLEVEL%"=="0" goto mainEnd
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:fail
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rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
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rem the _cmd.exe /c_ return code!
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if not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
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exit /b 1
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:mainEnd
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if "%OS%"=="Windows_NT" endlocal
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:omega
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13
kotlin/isbn-verifier/isbn-verifier.iml
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13
kotlin/isbn-verifier/isbn-verifier.iml
Normal file
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<?xml version="1.0" encoding="UTF-8"?>
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<module external.linked.project.id="isbn-verifier" external.linked.project.path="$MODULE_DIR$" external.root.project.path="$MODULE_DIR$" external.system.id="GRADLE" external.system.module.group="" external.system.module.version="unspecified" type="JAVA_MODULE" version="4">
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<component name="NewModuleRootManager" inherit-compiler-output="true">
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<exclude-output />
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<content url="file://$MODULE_DIR$">
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<excludeFolder url="file://$MODULE_DIR$/.gradle" />
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<excludeFolder url="file://$MODULE_DIR$/build" />
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<excludeFolder url="file://$MODULE_DIR$/out" />
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</content>
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<orderEntry type="inheritedJdk" />
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<orderEntry type="sourceFolder" forTests="false" />
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</component>
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</module>
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22
kotlin/isbn-verifier/src/main/kotlin/IsbnVerifier.kt
Normal file
22
kotlin/isbn-verifier/src/main/kotlin/IsbnVerifier.kt
Normal file
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class IsbnVerifier {
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fun isValid(inputString: String): Boolean {
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var count = 10
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val filteredString = inputString.filter { it != '-' }
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return if ((filteredString.all { it == 'X' || it.isDigit() })
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&& ((filteredString.indexOfFirst { it == 'X' } == 9)
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|| (filteredString.indexOfFirst { it == 'X' } == -1))
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&& (filteredString.length == 10)
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) {
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(filteredString
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.fold(0) { acc, c ->
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if (c == 'X') {
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count--
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acc + (10 * (count + 1))
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} else {
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count--
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acc + ((c.toInt() - 48) * (count + 1))
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}
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}.rem(11) == 0)
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} else false
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}
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}
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88
kotlin/isbn-verifier/src/test/kotlin/IsbnVerifierTest.kt
Normal file
88
kotlin/isbn-verifier/src/test/kotlin/IsbnVerifierTest.kt
Normal file
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import org.junit.Ignore
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import org.junit.Test
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import kotlin.test.assertFalse
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import kotlin.test.assertTrue
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class IsbnVerifierTest {
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private var isbnVerifier: IsbnVerifier = IsbnVerifier()
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@Test
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fun validIsbnNumber() {
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assertTrue(isbnVerifier.isValid("3-598-21508-8"))
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}
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@Test
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fun invalidIsbnCheckDigit() {
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assertFalse(isbnVerifier.isValid("3-598-21508-9"))
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}
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@Test
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fun validIsbnNumberWithCheckDigitOfTen() {
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assertTrue(isbnVerifier.isValid("3-598-21507-X"))
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}
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@Test
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fun checkDigitIsACharacterOtherThanX() {
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assertFalse(isbnVerifier.isValid("3-598-21507-A"))
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}
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@Test
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fun invalidCharacterInIsbn() {
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assertFalse(isbnVerifier.isValid("3-598-P1581-X"))
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}
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@Test
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fun xIsOnlyValidAsACheckDigit() {
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assertFalse(isbnVerifier.isValid("3-598-2X507-9"))
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}
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@Test
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fun validIsbnWithoutSeparatingDashes() {
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assertTrue(isbnVerifier.isValid("3598215088"))
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}
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@Test
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fun isbnWithoutSeparatingDashesAndXAsCheckDigit() {
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assertTrue(isbnVerifier.isValid("359821507X"))
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}
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@Test
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fun isbnWithoutCheckDigitAndDashes() {
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assertFalse(isbnVerifier.isValid("359821507"))
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}
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@Test
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fun tooLongIsbnAndNoDashes() {
|
||||
assertFalse(isbnVerifier.isValid("3598215078X"))
|
||||
}
|
||||
|
||||
@Test
|
||||
fun isbnWithoutCheckDigit() {
|
||||
assertFalse(isbnVerifier.isValid("3-598-21507"))
|
||||
}
|
||||
|
||||
@Test
|
||||
fun tooLongIsbn() {
|
||||
assertFalse(isbnVerifier.isValid("3-598-21507-XX"))
|
||||
}
|
||||
|
||||
@Test
|
||||
fun checkDigitOfXShouldNotBeUsedForZero() {
|
||||
assertFalse(isbnVerifier.isValid("3-598-21515-X"))
|
||||
}
|
||||
|
||||
@Test
|
||||
fun emptyIsbn() {
|
||||
assertFalse(isbnVerifier.isValid(""))
|
||||
}
|
||||
|
||||
@Test
|
||||
fun inputIsNineCharacters() {
|
||||
assertFalse(isbnVerifier.isValid("134456729"))
|
||||
}
|
||||
|
||||
@Test
|
||||
fun invalidCharactersAreNotIgnored() {
|
||||
assertFalse(isbnVerifier.isValid("3132P34035"))
|
||||
}
|
||||
}
|
||||
10
kotlin/rail-fence-cipher/src/main/kotlin/RailFenceCipher.kt
Normal file
10
kotlin/rail-fence-cipher/src/main/kotlin/RailFenceCipher.kt
Normal file
|
|
@ -0,0 +1,10 @@
|
|||
class RailFenceCipher(rows: Int) {
|
||||
fun getEncryptedData(inputString: String): String {
|
||||
|
||||
}
|
||||
|
||||
fun getDecryptedData(inputString: String): String {
|
||||
|
||||
}
|
||||
|
||||
}
|
||||
Loading…
Add table
Reference in a new issue