Regular Expressions 101

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// include the latest version of the regex crate in your Cargo.toml
extern crate regex;

use regex::Regex;

fn main() {
  let regex = Regex::new(r"(?m)back up code").unwrap();
  let string = "//9-digits phone number
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
    int n;
    string s;
    cin >> n;
    getline(cin,s);
    while(n--){
    	regex phone10(\"09[0-9]{2}(\\\\.[0-9]{3}){2}\");
	    string st;
	    getline(cin, st);
	    if(regex_match(st, phone10))
	        cout << \"Valid!\" << endl;
	    else
	        cout << \"Invalid!\" << endl;
	}
    
    return 0;
}



//11 digits phone number
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
	regex phone10(\"01[0-9]{9}\");
    string st;
    int n;
    cin >> n;
    getline(cin,st);
    while(n--){
	    getline(cin, st);
	    if(regex_match(st, phone10))
	        cout << \"Valid!\" << endl;
	    else
	        cout << \"Invalid!\" << endl;
	}
    
    return 0;
}



//alphabet string
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
	regex pattern(\"[a-zA-Z\\\\s]+\");
    string st;
    int n;
    cin >> n;
    getline(cin,st);
    while(n--){
	    getline(cin, st);
	    if(regex_match(st, pattern))
	        cout << \"Valid!\" << endl;
	    else
	        cout << \"Invalid!\" << endl;
	}
    
    return 0;
}



//Alpha-numberic Strings With Limited Length
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
	regex pattern(\"[a-z0-9]{6,20}\");
    string st;
    int n;
    cin >> n;
    getline(cin,st);
    while(n--){
	    getline(cin, st);
	    if(regex_match(st, pattern))
	        cout << \"Valid!\" << endl;
	    else
	        cout << \"Invalid!\" << endl;
	}
    
    return 0;
}



//bound checking for a Product
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

int main()
{
    unsigned int a,b;
    scanf(\"%u%u\",&a,&b);
    if(a!=0 && b!=0 && UINT_MAX/a<b)
        printf(\"No\");
    else
        printf(\"Yes\");
}



//bound checking for a Signed Product
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

int main()
{
    int a,b;
    scanf(\"%d%d\",&a,&b);
    if(a>0&&b>0){
        if(INT_MAX/a<b)
            printf(\"No\");
        else
            printf(\"Yes\");
    }
    else if(a<0&&b<0){
        if(INT_MAX/b>a)
            printf(\"No\");
        else
            printf(\"Yes\");
    }
    else if(a>0&&b<0){
        if(INT_MIN/a>b)
            printf(\"No\");
        else
            printf(\"Yes\");
    }
    else if(a<0&&b>0){
        if(INT_MIN/b>a)
            printf(\"No\");
        else
            printf(\"Yes\");
    }
    else
        printf(\"Yes\");

}



//bound checking for a Signed sum
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

int main()
{
    int a,b;
    scanf(\"%d%d\",&a,&b);
    if(a>0 && b>0 && b>INT_MAX-a)
        printf(\"No\");
    else if(a<0 && b<0 && b<INT_MIN-a)
        printf(\"No\");
    else
        printf(\"Yes\");
}



//Bound checking for a Sum
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

int main()
{
    unsigned int a,b;
    scanf(\"%u%u\",&a,&b);
    if(UINT_MAX-a>=b)
        printf(\"Yes\");
    else
        printf(\"No\");
}


//bound checking for an Integer
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
    char *s1 = (char*)malloc(12*sizeof(char));
    char *s2 = (char*)malloc(12*sizeof(char));
    gets(s1);
    int a = atoi(s1);
    sprintf(s2,\"%d\",a);
    if(strcmp(s1,s2)==0)
        printf(\"Yes\");
    else
        printf(\"No\");

}

//bound checking for the LCM
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

unsigned long long gcd(unsigned long long a, unsigned long long b) {
    unsigned long long temp = 0;
    while (b != 0)
    {
        temp = a % b;
        a = b;
        b = temp;
    }
    return a;
}

int main(void) {
	unsigned long long a, b;
    scanf(\"%llu %llu\", &a, &b);

    unsigned long long UCLN = gcd(a,b);
    if(a==0||b==0)
        printf(\"N/A\");
    else if((a/UCLN) <= (ULLONG_MAX/b))
        printf(\"%llu\",a/UCLN*b);
    else{
        printf(\"N/A\");
    }

	return 0;
}




//dual format telephone number
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
	regex phone10(\"(\\\\+84|0)1[0-9]{9}\");
    string st;
    int n;
    cin >> n;
    getline(cin,st);
    while(n--){
	    getline(cin, st);
	    if(regex_match(st, phone10))
	        cout << \"Valid!\" << endl;
	    else
	        cout << \"Invalid!\" << endl;
	}
    
    return 0;
}




//email address
#include <iostream>
#include <regex>
#include <string>
using namespace std;

int main(){
    regex pattern(\"([\\\\w!#$%&'*+/=?^_`{|}~-]+\\\\.?[\\\\w!#$%&'*+/=?^_`{|}~-]+)+@(\\\\w+(\\\\-\\\\w+)?(\\\\.\\\\w+))+\");
    int x;
    cin >>x;
    string line_;
    getline(cin,line_);
    while(x--){
        getline(cin,line_);
        if(regex_match(line_,pattern))
            cout << \"Valid!\"<<endl;
        else
            cout <<\"Invalid!\"<<endl;
    }
    return 0;
}



//find IP attack
#include <iostream>
#include <regex>
#include <string>
using namespace std;

int main(){
    regex pattern(\"\\\\d+\\\\ \\\\d+\\\\.\\\\d+(\\\\ ((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])\\\\.){3}(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])){2}\\\\ [A-Z]+\\\\ \\\\d+ [A-Z]+\\\\ [\\\\w-+/?=&.: ]+\");
    int t;
    string st;
    cin >> t;
    getline(cin, st);
    int i = 1;
    while(t--){
        getline(cin, st);
        cout << i++ << endl;
        sregex_token_iterator pos(st.cbegin(),st.cend(), pattern, 0);
        sregex_token_iterator end;
        for (; pos!=end; ++pos)
            cout << \"Found \" << pos->str() << endl;
    }
    return 0;
}



//integer number
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
	regex pattern(\"[\\\\+-]?[1-9][0-9]*\");
    string st;
    int n;
    cin >> n;
    getline(cin,st);
    while(n--){
	    getline(cin, st);
	    if(regex_match(st, pattern))
	        cout << \"Valid!\" << endl;
	    else
	        cout << \"Invalid!\" << endl;
	}
    
    return 0;
}




//list email in raw data
#include <iostream>
#include <regex>
#include <string>
using namespace std;

int main(){
    regex pattern(\"([\\\\w_-]+(\\\\.?[\\\\w_-]))+@[\\\\w]+([_\\\\w]+)?(\\\\.[\\\\w]+)+\");
    int t;
    string st;
    cin >> t;
    getline(cin, st);
    int i = 1;
    while(t--){
        getline(cin, st);
        cout << i++ << endl;
        sregex_token_iterator pos(st.cbegin(),st.cend(), pattern, 0);
        sregex_token_iterator end;
        for (; pos!=end; ++pos)
            cout << \"Found \" << pos->str()<< endl;
    }
    return 0;
}




//list IP in log web
#include <iostream>
#include <regex>
#include <string>
using namespace std;

int main(){
    regex pattern(\"((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])\\\\.){3}(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])\");
    int t;
    string st;
    cin >> t;
    getline(cin, st);
    int i = 1;
    while(t--){
        getline(cin, st);
        cout << i++ << endl;
        sregex_token_iterator pos(st.cbegin(),st.cend(), pattern, 0);
        sregex_token_iterator end;
        for (; pos!=end; ++pos)
            cout << \"Found \" << pos->str()<< endl;
    }
    return 0;
}




//list link in a tag HTML
#include <iostream>
#include <regex>
#include <string>
using namespace std;

int main(){
    regex pattern(\"(http|https|ftp)://[\\\\w\\\\.]+([-\\\\w\\\\.]+)?(:\\\\d+)?([/\\\\w]+)?\");
    int t;
    string st;
    cin >> t;
    getline(cin, st);
    int i = 1;
    while(t--){
        getline(cin, st);
        cout << i++ << endl;
        sregex_token_iterator pos(st.cbegin(),st.cend(), pattern, 0);
        sregex_token_iterator end;
        for ( ; pos!=end ; ++pos )
            cout << \"Found: \" << pos->str()<< endl;
    }
    return 0;
}



//list phone number
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
	regex pattern(\"((\\\\+84)|0)[1-9][0-9]{8,9}\");
    string st;
    int n;
    cin >> n;
    getline(cin, st);
    for(int i=1;i<=n;i++){
    	cout << i << endl;
    	getline(cin, st);
	    sregex_token_iterator pos(st.cbegin(),st.cend(), pattern, 0);
	    sregex_token_iterator end;
	    for ( ; pos!=end ; ++pos ) {
	        cout << \"Found \" << pos->str() << \" at \" << pos->first-st.begin() << endl;
	    }
	}    
    return 0;
}



//matching specific FileName
#include <iostream>
#include <regex>
#include <string>
using namespace std;

int main(){
    regex images(\"[a-zA-Z0-9\\\\_\\\\.]+\\\\.?[a-zA-Z0-9\\\\_]+\\\\.(([jJ][pP][gG])|([pP][nN][gG])|([gG][iI][fF]))\");
	regex docs(\"[a-zA-Z0-9\\\\_\\\\.]+\\\\.?[a-zA-Z0-9\\\\_]+\\\\.(([pP][dD][f|])|([dD][oO][cC])|([pP]{2}[tT][xX]))\");
	regex media(\"[a-zA-Z0-9\\\\_\\\\.]+\\\\.?[a-zA-Z0-9\\\\_]+\\\\.(([m|M][p|P][3|4])|([a|A][v|V][i|I]))\");
    int t;
    string st;
    cin >> t;
    getline(cin, st);
    int i = 1;
    while(t--){
        getline(cin, st);
        cout << i++ << endl;
        
        sregex_token_iterator pos(st.cbegin(),st.cend(), images, 0);
        sregex_token_iterator end;
        for ( ; pos!=end ; ++pos )
            cout << pos->str() << \" : \" << \"hinh anh\" << endl;
            
        sregex_token_iterator pos1(st.cbegin(),st.cend(), media, 0);
        sregex_token_iterator end1;
        for ( ; pos1!=end1 ; ++pos1 )
            cout << pos1->str() << \" : \" << \"media\" << endl;
            
        sregex_token_iterator pos2(st.cbegin(),st.cend(), docs, 0);
        sregex_token_iterator end2;
        for ( ; pos2!=end2 ; ++pos2 )
            cout << pos2->str() << \" : \" << \"tai lieu\" << endl;
    }
    return 0;
}




//modify telephone number
#include <iostream>
#include <regex>
#include <string>
using namespace std;

string Convert(string str){
    string temp = \"\";
    string sub = str.substr(0,4);
    if(sub.compare(\"0123\") ==0){
            regex at_sign(\"0123\");
            string replace_by(\"083\");
            temp = regex_replace(str, at_sign, replace_by);
    }else if(sub.compare(\"0124\") ==0){
            regex at_sign(\"0124\");
            string replace_by(\"084\");
            temp = regex_replace(str, at_sign, replace_by);
    }else if(sub.compare(\"0125\") ==0){
        regex at_sign(\"0125\");
            string replace_by(\"085\");
            temp = regex_replace(str, at_sign, replace_by);
    }
    else if(sub.compare(\"0127\") ==0){
            regex at_sign(\"0127\");
            string replace_by(\"081\");
            temp = regex_replace(str, at_sign, replace_by);
    }
    else if(sub.compare(\"0129\") ==0){
        regex at_sign(\"0129\");
            string replace_by(\"082\");
            temp = regex_replace(str, at_sign, replace_by);
    }
   return temp;
}
int main(){
    regex pattern(\"012[3-9^6]\\\\d{7}\");
    int t;
    string st;
    cin >> t;
    getline(cin, st);

    for(int i = 1; i <= t ; i++){
        getline(cin, st);
        cout << i << endl;
        sregex_token_iterator pos(st.cbegin(),st.cend(), pattern, 0);
        sregex_token_iterator end;
        for (; pos!=end; ++pos){
            string str1 = pos->str();
            cout << \"Thay doi:  \" << Convert(str1) << endl;
        }
    }
    return 0;
}



//numeric string leading without zero
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
	regex pattern(\"[1-9][0-9]*\");
    string st;
    int n;
    cin >> n;
    getline(cin,st);
    while(n--){
	    getline(cin, st);
	    if(regex_match(st, pattern))
	        cout << \"Valid!\" << endl;
	    else
	        cout << \"Invalid!\" << endl;
	}
    
    return 0;
}




//numeric string
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
	regex pattern(\"[0-9]*\");
    string st;
    int n;
    cin >> n;
    getline(cin,st);
    while(n--){
	    getline(cin, st);
	    if(regex_match(st, pattern))
	        cout << \"Valid!\" << endl;
	    else
	        cout << \"Invalid!\" << endl;
	}
    
    return 0;
}




//telephone number international format
#include<iostream>
#include<regex>
#include <string>
#include <stdexcept>
using namespace std;
int main()
{
	regex phone10(\"\\\\+841(\\\\.[0-9]{3}){3}\");
    string st;
    int n;
    cin >> n;
    getline(cin,st);
    while(n--){
	    getline(cin, st);
	    if(regex_match(st, phone10))
	        cout << \"Valid!\" << endl;
	    else
	        cout << \"Invalid!\" << endl;
	}
    
    return 0;
}



";
  
  // result will be an iterator over tuples containing the start and end indices for each match in the string
  let result = regex.captures_iter(string);
  
  for mat in result {
    println!("{:?}", mat);
  }
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Rust, please visit: https://docs.rs/regex/latest/regex/
Regular Expressions 101

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