Question

How to extract only digits from a string in C++

Answer 1

#include <iostream>
 
using namespace std; 

string extract_numbers(string s) { 
    int len = s.length(); 
    
    string number = ""; 
    for (int i = 0; i < len; i++) { 
        char ch = s.at(i); 
        if (isdigit(ch)) 
            number += ch; 
    } 
    return number;
} 
    
int main() 
{ 
    string s("c++14$vb.net&^java*() php <>/python 3.7.3"); 
  
    cout << extract_numbers(s);
      
    return 0; 
} 
  
  
/*
run:
  
14373
  
*/

 

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