C++ Tutorial/vector/vector insert

Combine insert and end to add elements to the end of vector

<source lang="cpp">#include <iostream>

1. include <cassert>
2. include <algorithm>
3. include <string>
4. include <list>
5. include <deque>
6. include <vector>

using namespace std; int main() {

 vector<string> vec;

 vec.insert(vec.end(), "AAA");
 vec.insert(vec.end(), "BBBB");
 vec.insert(vec.end(), "CCCCC");

 vector<string>::iterator pos;

 for (pos=vec.begin(); pos!=vec.end(); ++pos) {
       cout << *pos << " ";
 }
 return 0;

}</source>

AAA BBBB CCCCC

Insert 10 duplicate value to vector

<source lang="cpp">#include <iostream>

1. include <vector>

using namespace std; int main() {

 vector<char> v(10);
 vector<char> v2;
 char str[] = "<Vector>";
 unsigned int i;
 for(i=0; i<10; i++) 
    v[i] = i + "a";
 for(i=0; str[i]; i++) 
    v2.push_back(str[i]);
 
 cout << "Original contents of v:\n";
 for(i=0; i<v.size(); i++) 
     cout << v[i] << " ";
 cout << "\n\n";
 vector<char>::iterator p = v.begin();
 p += 2; // point to 3rd element
 v.insert(p, 10, "X");
 // display contents after insertion
 cout << "Size after inserting X"s = " << v.size() << endl;
 cout << "Contents after insert:\n";
 for(i=0; i<v.size(); i++) cout << v[i] << " ";
 cout << "\n\n";
 return 0;

}</source>

Original contents of v:
a b c d e f g h i j
Size after inserting X"s = 20
Contents after insert:
a b X X X X X X X X X X c d e f g h i j

Insert 25 at the beginning

<source lang="cpp">#include <vector>

1. include <iostream>

using namespace std; int main () {

   // Instantiate a vector with 4 elements, each initialized to 90
   vector <int> v (4, 90);
   // Insert 25 at the beginning
   v.insert (v.begin (), 25);
   
   vector <int>::iterator i;
   for ( i = v.begin (); i != v.end (); ++ i )
   {
       cout << *i << " ";
   }
   return 0;

}</source>

Insert 2 numbers of value 45 at the end

<source lang="cpp">#include <vector>

1. include <iostream>

using namespace std; int main () {

   // Instantiate a vector with 4 elements, each initialized to 90
   vector <int> v (4, 90);
   vector <int>::iterator i;
   for ( i = v.begin (); i != v.end (); ++ i ){
       cout << *i << " ";
   }
   // Insert 2 numbers of value 45 at the end
   v.insert (v.end (), 2, 45);
   cout << "The vector after inserting two elements at the end: ";
   for ( i = v.begin (); i != v.end (); ++ i )
   {
       cout << *i << " ";
   }
   return 0;

}</source>

Insert element by index

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

1. include <vector> // vector class-template definition
2. include <algorithm> // copy algorithm
3. include <iterator> // ostream_iterator iterator
4. include <stdexcept> // out_of_range exception

int main() {

  int array[ 6 ] = { 1, 2, 3, 4, 5, 6 };
  std::vector< int > integers( array, array + 6 );
  std::ostream_iterator< int > output( cout, " " );
  integers.push_back( 2 );
  integers.push_back( 3 );
  integers.push_back( 4 );
  cout << "Vector integers contains: ";
  std::copy( integers.begin(), integers.end(), output );
  // insert 22 as 2nd element
  integers.insert( integers.begin() + 1, 22 );
  cout << "\n\nVector integers contains: ";
  std::copy( integers.begin(), integers.end(), output );
  return 0;

}</source>

Vector integers contains: 1 2 3 4 5 6 2 3 4
Vector integers contains: 1 22 2 3 4 5 6 2 3 4

Insert elements from array

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

1. include <vector> // vector class-template definition
2. include <algorithm> // copy algorithm
3. include <iterator> // ostream_iterator iterator
4. include <stdexcept> // out_of_range exception

int main() {

  int array[ 6 ] = { 1, 2, 3, 4, 5, 6 };
  std::vector< int > integers( array, array + 6 );
  std::ostream_iterator< int > output( cout, " " );
  integers.push_back( 2 );
  integers.push_back( 3 );
  integers.push_back( 4 );
  cout << "Vector integers contains: ";
  std::copy( integers.begin(), integers.end(), output );
  // insert elements from array
  integers.insert( integers.begin(), array, array + 6 );
  cout << "\n\nContents of vector integers before clear: ";
  std::copy( integers.begin(), integers.end(), output );

  return 0;

}</source>

Vector integers contains: 1 2 3 4 5 6 2 3 4
Contents of vector integers before clear: 1 2 3 4 5 6 1 2 3 4 5 6 2 3 4

Insert one vector to another vector

<source lang="cpp">#include <iostream>

1. include <vector>

using namespace std; int main() {

 vector<char> v(10);
 vector<char> v2;
 char str[] = "<Vector>";
 unsigned int i;
 for(i=0; i<10; i++)
    v[i] = i + "a";
 for(i=0; str[i]; i++)
    v2.push_back(str[i]);
 cout << "Original contents of v:\n";
 for(i=0; i<v.size(); i++)
     cout << v[i] << " ";
 cout << "\n\n";
 vector<char>::iterator p = v.begin();
 p += 2; // point to 3rd element
 v.insert(p, 10, "X");
 // display contents after insertion
 cout << "Size after inserting X"s = " << v.size() << endl;
 cout << "Contents after insert:\n";
 for(i=0; i<v.size(); i++) cout << v[i] << " ";
 cout << "\n\n";

 // Insert v2 into v
 v.insert(p, v2.begin(), v2.end());
 cout << "Size after v2"s insertion = ";
 cout << v.size() << endl;
 cout << "Contents after insert:\n";
 for(i=0; i<v.size(); i++) cout << v[i] << " ";
 cout << endl;
 return 0;

}</source>

Original contents of v:
a b c d e f g h i j
Size after inserting X"s = 20
Contents after insert:
a b X X X X X X X X X X c d e f g h i j

Insert the contents of the array into the end of the vector

<source lang="cpp">#include <vector>

1. include <iostream>

using namespace std; int main(int argc, char** argv) {

 int arr[10]; // normal C++ array
 vector<int> vec; // STL vector
 int i;
 // Initialize each element of the array to the value of its index.
 for (i = 0; i < 10; i++) {
   arr[i] = i;
 }
 // Insert the contents of the array into the end of the vector.
 vec.insert(vec.end(), arr, arr + 10);
 // print the contents of the vector
 for (i = 0; i < 10; i++) {
   cout << vec[i] << " ";
 }
 return (0);

}</source>

Insert two elements from another container in position [1]

<source lang="cpp">#include <vector>

1. include <iostream>

using namespace std; int main () {

   // Instantiate a vector with 4 elements, each initialized to 90
   vector <int> v (4, 90);
   vector <int>::iterator i;
   for ( i = v.begin (); i != v.end (); ++ i ){
       cout << *i << " ";
   }
   vector <int> vecAnother (2, 30);
   v.insert (v.begin () + 1,vecAnother.begin (), vecAnother.end ());
   for ( i = v.begin (); i != v.end (); ++ i )
   {
       cout << *i << " ";
   }
   return 0;

}</source>