C++ Program to Implement Vector in STL

Vectors have the ability to resize itself automatically like dynamic arrays when an element is inserted or deleted, the container handle their storage automatically. Vector elements are placed in contiguous storage so that they can be accessed and traversed using iterators. Data can be inserted or erased at the begin, middle or end of the vector.

Functions and descriptions:

List of functions used here:
   v.size() = Returns the size of vector.
   v.push_back() = It is used to insert elements to the vector from end.
   v.pop_back() = To pop out the value from the vector from back.
   v.capacity() = Returns the size of the storage space currently allocated to the vector as number of elements.
   v.clear() = Clears the vector.

Example Code

#include <iostream>
#include <vector>
using namespace std;
int main() {
   vector<int> v;
   vector<int>::iterator it;
   int c, i;
   while (1) {
      cout<<"1.Size of the Vector"<<endl;
      cout<<"2.Insert Element into the Vector"<<endl;
      cout<<"3.Delete Last Element of the Vector"<<endl;
      cout<<"4.Display the capacity of vector"<<endl;
      cout<<"5.Display by Iterator"<<endl;
      cout<<"6.Clear the Vector"<<endl;
      cout<<"7.Exit"<<endl;
      cout<<"Enter your Choice: ";
      cin>>c;
      switch(c) {
         case 1:
            cout<<"Size of Vector: ";
            cout<<v.size()<<endl;
         break;
         case 2:
            cout<<"Enter value to be inserted: ";
            cin>>i;
            v.push_back(i);
         break;
         case 3:
            cout<<"Delete Last Element Inserted:"<<endl;
            v.pop_back();
         break;
         case 4:
            cout<<"Displaying capacity of vector: ";
            cout<<v.capacity()<<endl;
         break;
         case 5:
            cout<<"Displaying Vector by Iterator: ";
            for (it = v.begin(); it != v.end(); it++) {
               cout<<*it<<" ";
            }
            cout<<endl;
         break;
         case 6:
            v.clear();
            cout<<"Vector Cleared"<<endl;
         break;
         case 7:
            exit(1);
         break;
         default:
            cout<<"Wrong Choice"<<endl;
      }
   }
   return 0;
}

Output

1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 1
Size of Vector: 0
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 2
Enter value to be inserted: 7
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 2
Enter value to be inserted: 6
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 2
Enter value to be inserted: 4
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 2
Enter value to be inserted: 3
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 2
Enter value to be inserted: 5
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 4
Displaying capacity of vector: 8
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 5
Displaying Vector by Iterator: 7 6 4 3 5
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 3
Delete Last Element Inserted:
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 5
Displaying Vector by Iterator: 7 6 4 3
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 6
Vector Cleared
1.Size of the Vector
2.Insert Element into the Vector
3.Delete Last Element of the Vector
4.Display the capacity of vector
5.Display by Iterator
6.Clear the Vector
7.Exit
Enter your Choice: 7
Exit.