What is the use of the replace() in C++

**D-Mon** · 18-02-2010

Hi, How are you Everyone. I am the student of the MscIT. I have to submit the Project on the functions of the C++ language in three days. I can have the well knowledge of the functions that can be used in the C++ language. Even if, I can not know much more about the replace() function of the C++ language. So, I want to know about the replace() function of the C++ language. I also want to know What is the actual use of the replace() function in the C++ Programs. Reply Me!!

**Reegan** · 18-02-2010

Hello, According to my knowledge of the replace() function can be that the replace() function can be used in the C++ language to set all an elements in the given specified range [first,last) whose current value can equals old value to a value of new value. The behavior of the replace() function template can be similar to the following :

Code:

template < class FrwrdItrtr, class S >
  void replace ( FrwrdItrtr fst, FrwrdItrtr lst,
                 const S& oldvalue, const S& newvalue )
{
  for (; fst != lst; ++fst)
    if (*fst == oldvalue) *fst=newvalue;
}

**opaper** · 18-02-2010

The program that can be listed below describes you about the replace() function of the C++ language and how you can use the replace() function in the C++ program as :

Code:

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main () 
{
  int mint[] = { 10, 20, 30, 30, 20, 10, 10, 20 };
  vector<int> mvctr (mint, mint+8);      
  replace (mvctr.begin(), mvctr.end(), 20, 99); 
  cout << "mvctr contains:";
  for (vector<int>::iterator t=mvctr.begin(); t!=mvctr.end(); ++t)
    cout << " " << *t;
  cout << endl;
  return 0;
}

Output :

Code:

mvctr contains : 10 99 30 30 99 10 10 99

**MindSpace** · 18-02-2010

The replace() function can be used in the C++ language to replace the value of the particular an element in the given range. The following can be the general syntax of the replace() function :

Code:

template < class FrwrdItrtr, class S >
  void replace ( FrwrdItrtr fst, FrwrdItrtr lst,
                 const S& oldvalue, const S& newvalue );

**Modifier** · 18-02-2010

I suggest you to carefully go through the following code of lines that can be helpful for you to get the information or knowledge of the replace() function in the C++ language :

Code:

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main ()
 {
  int mya[] = { 10, 20, 30, 30, 20, 10, 10, 20 };
  vector<int> mvct (mya, mya+8);      
  replace (myvctr.begin(), myvctr.end(), 20, 99);
  cout << "myvctr contains:";
  for (vector<int>::aerator a=myvctr.begin(); a!=myvctr.end(); ++a)
    cout << " " << *a;
  cout << endl;
  return 0;
}

Output:

Code:

myvctr contains: 10 99 30 30 99 10 10 99

**Praetor** · 18-02-2010

The following can be the parameters of the replace() function in the C++ language :
1. newvalue : This parameter of the replace() function can have the replacement value of an element.
2. oldvalue : This parameter of the replace() function can have the Value that can be replaced.
3. fst, lst : These parameters of the replace() function can be used for the forward iterators to the final and starting positions in a given sequence. The range used can be as [first,last).