c++ - Replacing all occurrences of a substring with another substring in a long string -

i'm writing function, takes 3 parameters:

• target : target string
• oldval : old substring
• newval : new substring (to replace oldval)

the task of function find occurrence of oldval in target string, , replace them newval.

this function i've got @ moment:

std::string replace_old_with_new(std::string target, std::string oldval, std::string newval) {      std::cout << "target : " << target << ", oldval: " << oldval << ", newval: " << newval << "\n";     std::string::iterator begin = target.begin();     std::string::iterator oldvalbegin = oldval.begin();      while (begin != target.end()) {         if (*begin == *oldvalbegin) {             target = target.replace(begin, begin + oldval.size(), oldval);             begin = target.begin();         } else {             ++begin;         }     }      return target; } 

the following call above function:

replace_old_with_new("hello! hi hi!", "hi", "bye"); 

should return string -

"hello! bye bye!" 

but, when run code, nothing happens. seems i'm stuck in infinite loop. cursor keeps blinking on terminal. wrong function. think might troubling replace call in if block. correct way use iterator range in replace function call? can erase , insert. want use replace here.

strings smarter give them credit for. know how search, don't have yourself.

int pos = 0; int match_pos; std::string result; while ((match_pos = target.find(oldval, pos)) != std::string::npos) {     result += target.substr(pos, match_pos - pos);     result += newval;     pos = match_pos + target.size(); } result += target.substr(pos, std::string::npos); 

sorry, sketch; not tested, idea.