find_first_of()与 find_first_not_of()

#include<iostream>
#include<string>
using namespace std;
int main(){
 string s="ab2c3d7R4E6";
 string shuzi="0123456789";
 string zimu="abcdefghijklmnopqrstuvwxyz";
 
 string::size_type pop=0;
 while((pop=s.find_first_of(shuzi,pop))!=string::npos){
  cout<<s[pop]<<" ";
  ++pop;
 }
 cout<<endl;

 pop=0;

 while((pop=s.find_first_of(zimu,pop))!=string::npos){
  cout<<s[pop]<<" ";
  ++pop;
 }
 cout<<endl;
 return 0;
}

#include<iostream>
#include<string>
using namespace std;
int main(){
 string s="1d4e1w2w5we1s2a";
 string shuzi="0123456789";
 string zimu="abcdefghijklmnopqrstuvwxyz";

 string::size_type pop=0;
 while((pop=s.find_first_not_of(zimu,pop))!=string::npos){
  cout<<s[pop]<<" ";
  ++pop;
 }
 cout<<endl;

 pop=0;
 while((pop=s.find_first_not_of(shuzi,pop))!=string::npos){
   cout<<s[pop]<<" ";
   ++pop;
 }
 cout<<endl;
 return 0;
}

 

#include<iostream>
#include<string>
#include<cctype>
using namespace std;
int main(){
 string s="d1s2e4wrd12s";
 for(string::size_type t=0;t<s.size();++t){
  if(isdigit(s[t])){
   cout<<s[t]<<" ";
  }
 }
 cout<<endl;

 for(string::size_type tt=0;tt<s.size();++tt){
  if(isalpha(s[tt])){
   cout<<s[tt]<<" ";
  }
 }
 cout<<endl;
 return 0;
}