《Java语言程序设计(基础篇)》(第10版 梁勇 著)第二十七章练习题答案.pdf

《Java语言程序设计(基础篇)》(第10版梁勇著)

第二十七章练习题答案

27.1

publicclassExercise27_01{

/**Mainmethod/*

publicstaticvoidmain(String[]args)

{MyHashMap〈工nteger,Integermap=new

MyHashMap();map.put(2,2);

System.out.println(Iskey2inthemap?+map.containsKey(2));

map.remove(2);

System.out.println(Iskey2inthemap?+map.containsKey(2));

}

staticclassMyHashMapKJVimplementsMyMap〈K,V{

//Definethedefaulthashtablesize.

privatestaticintDEFAULT_INITIAL_CAPACITY=4;

//Definethemaximumhashtablesize.130issameas2A30

privatestaticintMAX工MUMJZAPAC工TY=130;

//Currenthashtablecapacity,

privateintcapacity;

//Definedefaultloadfactor

privatestaticfloatDEFAULT_MAX_LOAD_FACTOR=0.5f;

//Specifyaloadfactorusedinthehashtable

privatefloatloadFactorThreshold;

//Thenumberofentriesinthemap

privateintsize=0;

//Hashtableisanarraywitheachcellthatisalinkedlist

MyMap.EntryK^V[]table;

/**Constructamapwiththedefaultcapacityandloadfactor/*

publicMyHashMap(){

this(DEFAULT_INITIAL_CAPACITY,DEFAULT_MAX_LOAD_FACTOR)；

}

/**Constructamapwiththespecifiedinitialcapacityand

*defaultloadfactor/*

publicMyashMap(intinitialcapacity){

this(initialCapacity,DEFAULT_MAX_LOAD_FACTOR);

}

/**Constructamapwiththespecifiedinitialcapacity

*andloadfactor/*

publicMyashMap(intinitialcapacity,floatloadFactorThreshold){

this.capacity=initialcapacity;

this.loadFactorThreshold=loadFactorThreshold;

table=newMyMap.Entry[capacity];

}

/**Removealloftheentriesfromthismap/*

publicvoidclear()

{size=0;

removeEntries();

}

/**Returntrueifthespecifiedkeyisinthemap/*

publicbooleancontainsKey(Kkey){

if(get(