Explain about replace method with example ?

string& replace ( size_t pos1, size_t n1,   const string& str );string& replace ( iterator i1, iterator i2, const string& str );string& replace ( size_t pos1, size_t n1, const string& str, size_t pos2, size_t n2 );string& replace ( size_t pos1, size_t n1,   const char* s, size_t n2 );string& replace ( iterator i1, iterator i2, const char* s, size_t n2 );string& replace ( size_t pos1, size_t n1,   const char* s );string& replace ( iterator i1, iterator i2, const char* s );string& replace ( size_t pos1, size_t n1,   size_t n2, char c );string& replace ( iterator i1, iterator i2, size_t n2, char c );template<class InputIterator>   string& replace ( iterator i1, iterator i2, InputIterator j1, InputIterator j2 );Replace part of stringReplaces a section of the current string by some other content determined by the arguments passed.For the versions with parameters pos1 and n1, the section replaced begins at character position pos1 and spans for n1 characters within the string.For the versions with iterators i1 and i2, the section replaced is the one formed by the elements between iterator i1 and the element right before iterator i2.The arguments passed to the function determine what is the replacement for this section of the string:string& replace ( size_t pos1, size_t n1, const string& str );string& replace ( iterator i1, iterator i2, const string& str );    The section is replaced by a copy of the entire string object str.string& replace ( size_t pos1, size_t n1, const string& str, size_t pos2, size_t n2 );    The section is replaced by a copy of a substring of str. The substring is the portion of str that begins at the character position pos2 and takes up to n2 characters (it takes less than n2 if the end of the string is reached before).string& replace ( size_t pos1, size_t n1, const char * s, size_t n2 );string& replace ( iterator i1, iterator i2, const char * s, size_t n2 );    The section is replaced by a copy of the string formed by the first n2 characters in the array of characters pointed by s.string& replace ( size_t pos1, size_t n1, const char * s );string& replace ( iterator i1, iterator i2, const char * s );    The section is replaced by a copy of the string formed by the null-terminated character sequence (C string) pointed by s. The length of this character sequence is determined by the first ocurrence of a null character (as determined by traits.length(s)).string& replace ( size_t pos1, size_t n1, size_t n2, char c );string& replace ( iterator i1, iterator i2, size_t n2, char c );    The section is replaced by a repetition of character c, n2 times.template<class InputIterator> string& replace (iterator i1, iterator i2, InputIterator j1, InputIterator j2);    The section is replaced by the content made up of the characters that go from the element referred by iterator j1 to the element right before the one referred by iterator j2.// replacing in a string#include <iostream>#include <string>using namespace std;int main (){  string base="this is a test string.";  string str2="n example";  string str3="sample phrase";  string str4="useful.";  // function versions used in the same order as described above:  // Using positions:                 0123456789*123456789*12345  string str=base;                // "this is a test string."  str.replace(9,5,str2);          // "this is an example string."  str.replace(19,6,str3,7,6);     // "this is an example phrase."  str.replace(8,10,"just all",6); // "this is just a phrase."  str.replace(8,6,"a short");     // "this is a short phrase."  str.replace(22,1,3,'!');        // "this is a short phrase!!!"  // Using iterators:                      0123456789*123456789*  string::iterator it = str.begin();   //  ^  str.replace(it,str.end()-3,str3);    // "sample phrase!!!"  str.replace(it,it+6,"replace it",7); // "replace phrase!!!"  it+=8;                               //          ^  str.replace(it,it+6,"is cool");      // "replace is cool!!!"  str.replace(it+4,str.end()-4,4,'o'); // "replace is cooool!!!"  it+=3;                               //             ^  str.replace(it,str.end(),str4.begin(),str4.end());                                       // "replace is useful."  cout << str << endl;  return 0;}Output:replace is useful.