Application of Andy s first dictionary (uva10815) Purple Book p112set

Purple Book P112;set Application ;Andy’s First Dictionary(UVa10815);

Vjudge Please move the title address here

The main idea of the topic ：

Enter a text （ most 500 That's ok , The most in each line 200 Characters , With EOF ending ）, Find all the different words , Output in lowercase from small to large in dictionary order （ One word per line ）.

Sample Input

Adventures in Disneyland

Two blondes were going to Disneyland when they came to a fork in the

road. The sign read: “Disneyland Left.”

So they went home.

Sample Output
a
adventures
blondes
came
disneyland
fork
going
home
in
left
read
road
sign
so
the
they
to
two
went
were
when

Topic analysis ：

data structure choice ： Count the words that appear , Of course set;

Algorithm design ： Violent simulation , Time O(n) Maximum 100000; Read a string of characters at a time ,for Loop to determine whether a single character is a letter , If converted to lowercase , If it is not , Then save the words formed by the read letters , Start reading the next word again ;

//dict by set aggregate ,s For the currently read string ,now A word consisting of the currently stored letters 
if(isalpha(s[i])){
    
		  	 	 now+=tolower(s[i]);
			 }else{
    
			 	 if(!now.empty()) dict.insert(now);
			 	 now.clear();
			 }

Module design ： Definition and pretreatment – Read in and initialize – Processing strings – Output –return 0;

Code ：

#include<iostream>
#include<set>
#include<cctype>
#include<string>
using namespace std;

struct rule{
    
	 bool operator()(const string &a,const string &b){
    
	 	 return a<b;
	 }
};

set<string,rule> dict;
string s;

int main()
{
    
	 while(cin>>s)
	 {
    
	 	 string now;
	 	 now.clear();
	 	 for(int i=0;i<s.length();i++)
		 {
    
		  	 if(isalpha(s[i])){
    
		  	 	 now+=tolower(s[i]);
			 }else{
    
			 	 if(!now.empty()) dict.insert(now);
			 	 now.clear();
			 }
		 }
		 if(!now.empty()) dict.insert(now);
	 }
	 for(set<string>::iterator i=dict.begin();i!=dict.end();i++)//auto i=dict.begin();
	 	 cout<<*i<<endl;
	 return 0;
}

Summary of key points and details ：

1. The code uses a string handler isalpha() And tolower();
   isalpha()： Decide if it's a letter ;
   islower()： Decide if it's lowercase ;
   isupper()： Decide if it's capital ;
   tolower()： Convert to lowercase ;
   toupper()： Convert to uppercase ;
2. set Insertion insert() If a duplicate value is encountered, it is invalid ;
3. Code for now Can be replaced by an input stream ： Non alphabetic conversion to space encountered , And then to s Stream input processing , Header file required #include<sstream>;

for(int i=0;i<s.length();i++)
	 if(isalpha(s[i])) s[i]=tolower(s[i]); else s[i]=' ';
stringstream ss(s);
while(ss>>buf) dict.insert(buf);

4. Define iterators in your code set<string>::iterator i=dict.begin(); You can use more concise auto i=dict.begin() Replace .

Update and 2020.6.23