string.cpp

数据结构实验课中的所有实验程序

// String.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "iostream.h"
#include "String00.h"
#include "string.h"
#include "stdlib.h" 

# define maxlen 128

String00::String00(const String00 & ob)
{ch=new char[maxlen+1];
 if(!ch) { cerr<<"Allocation Error\n"; exit(1);}
  curlen=ob.curlen;
  strcpy(ch,ob.ch);
}

String00:: String00(const char *init){

ch=new char[maxlen+1];
	 if(!ch) { cerr<<"Allocation Error\n"; exit(1);}
	 curlen=strlen(init);
	 strcpy(ch,init);	 

}
String00:: String00(){

ch=new char[maxlen+1];
	 if(!ch) { cerr<<"Allocation Error\n"; exit(1);}
	 curlen=0;
	 ch[0]='\0';
}


	
	 
String00 &String00:: operator()(int pos,int len){
     String00 * temp=new String00();
	 if(pos<0||pos+len-1>=maxlen||len<0){
	   temp->curlen=0; temp->ch[0]='\0';
	 }
	 else {
	      if(pos+len-1>=curlen)len=curlen-pos;
		  temp->curlen=len;
		  for(int i=0,j=pos;i<len;i++,j++)
			  temp->ch[i]=ch[j];
		     temp->ch[len]='\0';
	 }
        return *temp;
}
	
	 String00 &String00::operator=(const String00 &ob)
	 {
		 if(&ob!=this){
            delete[]ch;
			ch=new char[maxlen+1];
			if(!ch){cerr<<"out of memory!\n"; exit(1);}
			curlen=ob.curlen;
			strcpy(ch,ob.ch);
		 }
		 else cout<<"Attempted assignment of a String to itself! \n";
		 return *this;
	 }
 String00 &String00:: operator +=(const String00 & ob)
 {
    char * temp=ch;
	curlen+=ob.curlen;
if(!ch){cerr<<"out of memory!\n"; exit(1);}
   strcpy(ch,temp);
   strcat(ch,ob.ch);
   delete[]temp;return *this;
 
 }

 char &String00::operator[](int i){
 if(i<0&&i>=curlen)
 {cout<<"Out Of Boundary! \n";exit(1);}
 return ch[i];
 
 }
 int String00::Find(String00 & pat)const{
  char *p=pat.ch,*s=ch;int i=0;
  if(*p&&*s)
	  while(i<=curlen-pat.curlen)
		  if(*p++ == * s ++){
		  if(!*p) return i;
		  }
		  else{i++;s=ch+i;p=pat.ch;}
		  return -1;
 }

 int String00::count(String00 & pat){
 if(this->Find(pat)!=-1)
 {char *p=pat.ch,*s=ch;int i=0;int j=0;
  if(*p&&*s)
	  while(i<=curlen-pat.curlen)
		  if(*p++ == * s ++){
		  if(!*p) j++; }
		 else{i++;s=ch+i;p=pat.ch;}
		 return j;
 }
 else return 0;
 }

void main(int argc, char* argv[]){
  int i=1;
  int loc,len;
char str[20]="dfsabcdabste";
String00 obj(str);
cout<<obj.get()<<endl;
cout<<"the length of the string is "<<obj.length()<<endl;
cout<<"please input the location of the substring:"<<endl;
cin>>loc;
cout<<"please input the length of the substring:"<<endl;
cin>>len;
cout<<obj(loc,len).get()<<endl;
String00 obj1;
cout<<"now copy the original string"<<endl;
obj1=obj;
cout<<"the new string is "<<obj1.get()<<endl;
char sub[]="ab";
String00 obj2(sub);
cout<<"the letter 'ab'exist in the string?";
if(obj.Find(obj2)!=-1) cout<<"true"<<endl;
else cout<<"false"<<endl;
cout<<"'ab' appear in string "<<obj.count(obj2)<<" times"<<endl;
}