Deque Operator Function

The operator function in C++ Deque is utilized to retrieve the element located at a specific position referred to as pos. In case pos exceeds the container's size, it will return a value of 0.

Difference between operator__PRESERVE_5__ & at

When the index pos exceeds the container's size, the operator function yields a value of 0, whereas the at function raises an out-of-range exception.

Syntax

reference operator[] (int pos);

Parameter

It specifies the location of an element that needs to be retrieved.

Return value

It provides a reference to an element located at the specified position pos within the deque container.

Example 1

Let's see a simple example

#include <iostream>
#include<deque>
using namespace std;
int main()
{
   
  deque<string> a={"mango","is","my","favorite","fruit"};
   for(int i=0;i<a.size();i++)
  {
      cout<<a.operator[](i);
      cout<<" ";
  }
    return 0;
}

Output:

mango is my favorite fruit

In this instance, the operator method is utilized to access every element within deque a.

Example 2

Let's explore a basic scenario where the position (pos) is beyond the allowable range.

#include <iostream>
#include<deque>
using namespace std;
int main()
{
     deque<int> a={1,2,3,4,5,6};
  
  cout<<a.operator[](7);
  return 0;
}

Output:

In this instance, the operator function attempts to retrieve a position beyond the container's size, resulting in a return value of 0.