insert()用于在字符串中的指定位置插入字符。它支持各种语法以促进相同，在这里我们将对其进行描述。
语法1：从索引idx插入str的字符。
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.
// CPP code for insert (size_type idx, const string& str)
#include
#include
using namespace std;
// Function to demonstrate insert
void insertDemo(string str1, string str2)
{
// Inserts str2 in str1 starting
// from 6th index of str1
str1.insert(6, str2);
cout << "Using insert : ";
cout << str1;
}
// Driver code
int main()
{
string str1("Hello World! ");
string str2("GeeksforGeeks ");
cout << "Original String : " << str1 << endl;
insertDemo(str1, str2);
return 0;
}
输出：
Original String : Hello World!
Using insert : Hello GeeksforGeeks World!
语法2：最多插入str的str_num个字符，从索引str_idx开始。
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.
// CPP code for insert (size_type idx, const string& str,
// size_type str_idx, size_type str_num)
#include
#include
using namespace std;
// Function to demonstrate insert
void insertDemo(string str1, string str2)
{
// Inserts 6 characters from index number
// 8 of str2 at index number 6 of str1
str1.insert(6, str2, 8, 6);
cout << "Using insert : ";
cout << str1;
}
// Driver code
int main()
{
string str1("Hello World! ");
string str2("GeeksforGeeks ");
cout << "Original String : " << str1 << endl;
insertDemo(str1, str2);
return 0;
}
输出：
Original String : Hello World!
Using insert : Hello Geeks World!
语法3：插入的C-串CSTR，以使新的字符会以指数IDX的字符。
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.
注意： cstr可能不是空指针(NULL)。
// CPP code for insert(size_ type idx, const char* cstr)
#include
#include
using namespace std;
// Function to demonstrate insert
void insertDemo(string str)
{
// Inserts " are " at 5th index of str
str.insert(5, " are ");
cout << "Using insert : ";
cout << str;
}
// Driver code
int main()
{
string str("GeeksforGeeks ");
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
输出：
Original String : GeeksforGeeks
Using insert : Geeks are forGeeks
语法4：插入字符数组chars的chars_len字符，以便新字符以索引idx开头。
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.
注意：char必须至少包含chars_len个字符。
// CPP code for insert (size_type idx, const char* chars,
// size_type chars_len)
#include
#include
using namespace std;
// Function to demonstrate insert
void insertDemo(string str)
{
// Inserts 10 characters from" are here "
// at 5th index of str
str.insert(5, " are here ", 10);
cout << "Using insert : ";
cout << str;
}
// Driver code
int main()
{
string str("GeeksforGeeks ");
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
输出：
Original String : GeeksforGeeks
Using insert : Geeks are here forGeeks
语法5：在idx指定的位置插入num个出现的字符c。
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.// CPP code for :insert (size_type idx, size_type num, char c)
#include
#include
using namespace std;
// Function to demonstrate insert
void insertDemo(string str)
{
// Inserts at 5th index,
// 5 occurrences of '$'
str.insert(5, 5, '$');
cout << "Using insert : ";
cout << str;
}
// Driver code
int main()
{
string str("**********");
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
输出：
Original String : **********
Using insert : *****$$$$$*****
语法6：在迭代器pos指定的位置插入num个出现的字符c。
void string ::insert (iterator pos, size_type num, char c)
pos : is the position of iterator.
c : is the character which is to be inserted.
Returns : *this
Errors:
Throws out_of_range if pos > size().
Throws length_error if the resulting size exceeds the maximum number of characters.
// CPP code for :insert (iterator pos, size_type num, char c)
#include
#include
using namespace std;
// Function to demonstrate insert
void insertDemo(string str)
{
// Inserts 5 occurrences of '$'
// at position str.begin() + 5
str.insert(str.begin() + 5, 5, '$');
cout << "Using insert : ";
cout << str;
}
// Driver code
int main()
{
string str("**********");
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
输出：
Original String : **********
Using insert : *****$$$$$*****
语法7：插入到迭代器POS是指在字符前字符c的副本。
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.
// CPP code for :insert (iterator pos, char c )
#include
#include
using namespace std;
// Function to demonstrate insert
void insertDemo(string str)
{
std::string::iterator pos;
// Inserts '$' at position
// str.begin() + 5
pos = str.insert(str.begin()+5,'$');
cout << "Using insert : ";
cout << str << endl;
cout << "Value at Iterator returned : " << *pos;
}
// Driver code
int main()
{
string str("**********");
cout << "Original String : " << str << endl;
insertDemo(str);
return 0;
}
输出：
Original String : **********
Using insert : *****$*****
Value at Iterator returned : $
语法8：将范围为[beg，end)的所有字符插入迭代器pos所引用的字符之前。
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.
// CPP code for insertinsert (iterator pos, InputIterator beg,
// InputIterator end )
#include
#include
using namespace std;
// Function to demonstrate insert
void insertDemo(string str1, string str2)
{
// Inserts str2.begin() + 5 , str2.end() - 6
// at position str1.begin() + 6
str1.insert(str1.begin() + 6, str2.begin() + 5 , str2.end() - 6);
cout << "Using insert : ";
cout << str1;
}
// Driver code
int main()
{
string str1("Hello World! ");
string str2("GeeksforGeeks ");
cout << "Original String : " << str1 << endl;
insertDemo(str1, str2);
return 0;
}
输出：
Original String : Hello World!
Using insert : Hello forWorld!
要从最佳影片策划和实践问题去学习，检查了C++基础课程为基础，以先进的C++和C++ STL课程基础加上STL。要完成从学习语言到DS Algo等的更多准备工作，请参阅“完整面试准备课程” 。