std::string inserting

Inserting:-
Inserting characters into an existing string can be done via the insert() function.

string& string::insert (size_type index, const string& str) string& string::insert (size_type index, const char* str) Both functions insert the characters of str into the string at index Both function return *this so they can be “chained”. Both functions throw out_of_range if index is invalid Both functions throw a length_error exception if the result exceeds the maximum number of characters. In the C-style string version, str must not be NULL. Sample code: 1 string sString("aaaa"); 2 cout << sString << endl; 3 4 sString.insert(2, string("bbbb")); 5 cout << sString << endl; 6 7 sString.insert(4, "cccc"); 8 cout << sString << endl; Output: aaaa aabbbbaa aabbccccbbaa

Here’s a crazy version of insert() that allows you to insert a substring into a string at an arbitrary index:
There is a flavor of insert() that inserts the first portion of a C-style string:

string& string::insert(size_type index, const char* str, size_type len) Inserts len characters of str into the string at index Returns *this so it can be “chained”. Throws an out_of_range exception if the index is invalid Throws a length_error exception if the result exceeds the maximum number of characters. Ignores special characters (such as ‘\0′) Sample code: 1 string sString("aaaa"); 2 3 sString.insert(2, "bcdef", 3); 4 cout << sString << endl; Output: aabcdaa

There’s also a flavor of insert() that inserts the same character multiple times:

string& string::insert(size_type index, size_type num, char c) Inserts num instances of char c into the string at index Returns *this so it can be “chained”. Throws an out_of_range exception if the index is invalid Throws a length_error exception if the result exceeds the maximum number of characters. Sample code: 1 string sString("aaaa"); 2 3 sString.insert(2, 4, 'c'); 4 cout << sString << endl; Output: aaccccaa

And finally, the insert() function also has three different versions that use iterators:
void insert(iterator it, size_type num, char c)
iterator string::insert(iterator it, char c)
void string::insert(iterator it, InputIterator begin, InputIterator end)

• The first function inserts num instances of the character c before the iterator it.
• The second inserts a single character c before the iterator it, and returns an iterator to the position of the character inserted.
• The third inserts all characters between [begin,end) before the iterator it.
• All functions throw a length_error exception if the result exceeds the maximum number of characters.