std::string::insert() in C++
insert() is used to insert characters in string at specified position. It supports various syntaxes to facilitate same, here we will describe them.
Syntax 1: Inserts the characters of str starting from index idx.
string& string::insert (size_type idx, const string& str)
idx :is the index number
str : is the string from which characters is to be picked to insert
Returns *this.
Errors:
Throws out_of_range if idx > size().
Throws length_error if the resulting size exceeds the maximum number of characters.
#include <iostream>
#include <string>
using namespace std;
void insertDemo(string str1, string str2)
{
str1.insert(6, str2);
cout << "Using insert : " ;
cout << str1;
}
int main()
{
string str1( "Hello World! " );
string str2( "GeeksforGeeks " );
cout << "Original String : " << str1 << endl;
insertDemo(str1, str2);
return 0;
}
|
Output:
Original String : Hello World!
Using insert : Hello GeeksforGeeks World!
Syntax 2: Inserts at most, str_num characters of str, starting with index str_idx.
string& string::insert (size_type idx, const string& str, size_type str_idx,
size_type str_num)
idx : is the index number where insertion is to be made.
str : is the string from which characters are to be picked to insert.
str_idx : is the index number in str.
str_num : is the number of characters to be inserted from str.
Returns *this.
Errors:
Throws out_of_range if idx > size().
Throws out_of_range if str_idx > str.size().
Throws length_error if the resulting size exceeds the maximum number of characters.
#include <iostream>
#include <string>
using namespace std;
void insertDemo(string str1, string str2)
{
str1.insert(6, str2, 8, 6);
cout << "Using insert : " ;
cout << str1;
}
int main()
{
string str1( "Hello World! " );
string str2( "GeeksforGeeks " );
cout << "Original String : " << str1 << endl;
insertDemo(str1, str2);
return 0;
}
|
Output:
Original String : Hello World!
Using insert : Hello Geeks World!
Syntax 3: Inserts the characters of the C-string cstr so that the new characters start with index idx.
string& string::insert (size_ type idx, const char* cstr)
idx : is the index number where insertion is to be made.
*cstr : is the pointer to the C-string which is to be inserted.
Returns *this.
Errors:
Throws out_of_range if idx > size().
Throws length_error if the resulting size exceeds the maximum number of characters.
Note: cstr may not be a null pointer (NULL).
#include <iostream>
#include <string>
using namespace std;
void insertDemo(string str)
{
str.insert(5, " are " );
cout << "Using insert : " ;
cout << str;
}
int main()
{
string str( "GeeksforGeeks " );
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
|
Output:
Original String : GeeksforGeeks
Using insert : Geeks are forGeeks
Syntax 4: Inserts chars_len characters of the character array chars so that the new characters start with index idx.
string& string::insert (size_type idx, const char* chars, size_type chars_len)
idx : index number where insertion is to be made.
*chars : is the pointer to the array.
chars_len : is the number of characters to be inserted from character array.
Returns : *this
Errors:
Throws out_of_range if idx > size().
Throws length_error if the resulting size exceeds the maximum number of characters.
Note : chars must have at least chars_len characters.
#include <iostream>
#include <string>
using namespace std;
void insertDemo(string str)
{
str.insert(5, " are here " , 10);
cout << "Using insert : " ;
cout << str;
}
int main()
{
string str( "GeeksforGeeks " );
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
|
Output:
Original String : GeeksforGeeks
Using insert : Geeks are here forGeeks
Syntax 5: Inserts num occurrences of character c at the position specified by idx.
string& string ::insert (size_type idx, size_type num, char c)
idx : is the index number where insertion is to be made.
c : is the character to be inserted.
num : is the number of repetition of character c
Returns : *this
Errors:
Throw out_of_range if idx > size().
Throw length_error if the resulting size exceeds the maximum number of characters.
#include <iostream>
#include <string>
using namespace std;
void insertDemo(string str)
{
str.insert(5, 5, '$' );
cout << "Using insert : " ;
cout << str;
}
int main()
{
string str( "**********" );
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
|
Output:
Original String : **********
Using insert : *****$$$$$*****
Syntax 6: Inserts num occurrences of character c at the position specified by iterator pos.
void string ::insert (iterator pos, size_type num, char c)
pos : is the position of iterator.
c : is the character which is to be inserted.
Returns : *this
Errors:
Throws out_of_range if pos > size().
Throws length_error if the resulting size exceeds the maximum number of characters.
#include <iostream>
#include <string>
using namespace std;
void insertDemo(string str)
{
str.insert(str.begin() + 5, 5, '$' );
cout << "Using insert : " ;
cout << str;
}
int main()
{
string str( "**********" );
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
|
Output:
Original String : **********
Using insert : *****$$$$$*****
Syntax 7: Inserts a copy of character c before the character to which iterator pos refers.
iterator string ::insert (iterator pos, char c )
pos : is the position of iterator.
c : is the character which is to be inserted.
Returns : iterator pointing to the first character inserted.
Error:
Throws length_error if the resulting size exceeds the maximum number of characters.
#include <iostream>
#include <string>
using namespace std;
void insertDemo(string str)
{
std::string::iterator pos;
pos = str.insert(str.begin()+5, '$' );
cout << "Using insert : " ;
cout << str << endl;
cout << "Value at Iterator returned : " << *pos;
}
int main()
{
string str( "**********" );
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
|
Output:
Original String : **********
Using insert : *****$*****
Value at Iterator returned : $
Syntax 8: Inserts all characters of the range [ beg,end ) before the character to which iterator pos refers.
void string ::insert (iterator pos, InputIterator beg, InputIterator end )
pos : is the iterator position.
beg, end : Input iterators to the initial and final positions in a sequence.
Error:
Throws length_error if the resulting size exceeds the maximum number of characters.
#include <iostream>
#include <string>
using namespace std;
void insertDemo(string str1, string str2)
{
str1.insert(str1.begin() + 6, str2.begin() + 5 , str2.end() - 6);
cout << "Using insert : " ;
cout << str1;
}
int main()
{
string str1( "Hello World! " );
string str2( "GeeksforGeeks " );
cout << "Original String : " << str1 << endl;
insertDemo(str1, str2);
return 0;
}
|
Output:
Original String : Hello World!
Using insert : Hello forWorld!
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Last Updated :
10 Sep, 2018
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