数据结构复习10 串

string.h

/* string DIY process must be the most important in our job */
/* string is a sequent list limited */
/* string.h
--int strcpy(s1,s2) copy s2 content to s1 **if s1 bigger than s2,the front content will be reaplaced,with remain the last content
--int strcat(s1,s2) put s2 to s1's rear part
--int strlen(s) count the size of string
--char* _strdup(s) char *p=_strdup(s); generate string by an another string
--int strcmp(s1,s2) 
 */

字符串ADT

/* string DIY process must be the most important in our job */
/* string is a sequent list limited */
/* string.h
--int strcpy(s1,s2) copy s2 content to s1 **if s1 bigger than s2,the front content will be reaplaced,with remain the last content
--int strcat(s1,s2) put s2 to s1's rear part
--int strlen(s) count the size of string
--char* _strdup(s) char *p=_strdup(s); generate string by an another string
--int strcmp(s1,s2) 
 */
 
#define MAX 1000
typedef char OrderString[MAX];

class MyString{
	protected:
	char *ch;
	int length;
	int maxSize;
	public:
	MyString(int size=MAX);
	MyString(const char *init);//strlen strcpy
	MyString(const MyString& ms);//strlen strcpy
	~MyString(){delete []ch;}
	int Length()const{return length;}
	MyString& operator()(int pos,int len);
	int operator==(MyString& ms)const{return strcmp(ch,ms.ch)==0;}
	int operator!=(MyString& ms)const{return strcmp(ch,ms.ch)!=0;}
	int operator!()const(return length==0;}
	MyString& operator=(const MyString& ms);
	MyString& operator+=(const MyString& ms);//strcat
	char& operator[](int i);
	int KMPFind(MyString &pat)const;
	void getNext(int next[]);
};

MyString::MyString(int size):maxSize(size){
	ch=new char[maxSize+];
	assert(ch!=NULL);
	length=0;ch[0]='\0';
}

MyString(const char *init){
	int len=strlen(init);
	maxSize=(len>MAX)?len:MAX;
	ch=new char[maxSize+1];
	assert(ch!=NULL);
	length=len;
	strcpy(ch,init);
}

MyString MyString::(const MyString &ms){
	maxSize=ms.maxSize;
	ch=new char[ms.length+1];
	assert(ch!=NULL);
	length=ms.length;
	strcpy(ch,ms.ch);
}

MyString MyString::operator()(int pos,int len){
	MyString temp;
	if(pos<0 || pos+len>=maxSize+1 || len<0){
		temp.length=0;temp.ch[0]='\0';
	}else{
		//len in sense
		if(pos+len>=length+1)
			len=length-pos;
		//get substr
		temp.len=len;
		for(int i=0,j=pos;i<len;i++,j++)
			temp.ch[i]=ch[j];
		temp.ch[len]='\0';
	}
	return temp;
}

MyString& MyString::operator=(const MyString& ms){
	if(this==&ms){
		return ms;
	}
	delete []ch;
	ch=new char[ms.maxSize+1];
	assert(ch!=NULL);
	length=ms.length;
	strcpy(ch,ms.ch);
	return *this;
}

MyString& MyString::operator+=(const MyString& ms){
	//strcat
	//bigger than maxSize
	char *temp=ch;
	int n=length+ms.length;
	int m=(n>=maxSize)?maxSize:n;
	ch=new char[m];
	assert(ch!=NULL);
	//catch
	maxSize=m;
	length=n;
	strcpy(ch,temp);
	strcat(ch,ms.ch);
	delete []temp;
	return *this;
	
}

char& MyString::operator[](int i){
	assert(!(i<0||i>=length));
	return ch[i];
}

int MyString::KMPFind(MyString &pat,int k,int next[])const{
	int posT=k;
	int posP=0;
	int lenP=pat.length;
	int lenT=length;
	while(posT<lenT&&posP<lenP){
		if(posP==-1||pat.ch[posP]==ch[posT]){
			posT++;posP++;//B-F part
		}
		else{
			posP=next[posP];//K-M-P part
		}
	}
	if(posT>=lenT || posP<lenP)
		//matching failed
		return -1;
	else
		//return first index in Tstring
		return posT-lenP;
}

void MyString::getNext(int next[]){
	int j=0;
	int k=-1;
	int lenP=length;
	next[0]=-1;
	while(j<lenP){
		if(k==-1||ch[j]==ch[k]){
			j++;k++;
			next[j]=k;
		}else{
			
			k=next[k];
		}
	}
}