#include <stdio.h>
#include <string>
#include <iostream>
 
using std::cout;
using std::endl;
using std::string;
 
 
bool find_value_from_key(const string& source, const string& key, string& value, const string& endmarkers) {
   bool ret = false;
   size_t key_start = source.find(key);
   size_t val_start = key_start + key.length();
   if(key_start != string::npos) {
      size_t val_end = source.find_first_of(endmarkers, val_start);
      if(val_end == string::npos && source.length() > val_start)
         val_end = source.length();
 
      if(val_end != string::npos) {
         value = source.substr(val_start, val_end - val_start);
         ret = true;
      }
   }
   return ret;
}
 
int main(int argc, char* argv[])
{
   //test strings to exercise find_value_from_key function 
   const char* test_strings[] = {
      "key1 = value1", 
      "   key1 = value1   ", 
      "key1 = value1,key2 = value2 ,key3 = value3",
      "_key1 = value1 ,key2 = value2 ,Gkey3 = value3,", 
      "key1 = value1,key2 =  value2 ,key3 = value3 x", 
      "key1 = value1,key2 = value2key3 = value3\n", 
      "key1 = value1_,key2 = value2 ,key3 = value3                    ", 
      "key1 = value1$,key2 = value2 ,key3 =   value3", 
      "key1 = value1\t,key2 = value2  ,key3 = value3\t" };
 
   const char* keys[] = {"key1 = ", "key2 = ", "key3 = "};
 
   int elements = sizeof(test_strings) / sizeof(test_strings[0]);
 
   for(int i = 0; i < elements; ++i) {
     cout << "processing: " << test_strings[i] << endl;
     string value;
     for (int k = 0; k < 3; k++) {
       if(find_value_from_key(test_strings[i], keys[k], value, ", \t\n"))
          cout << keys[k] << " -> " << value << endl;
     }
   }
 
   return 0;
}

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