C++ map begin() Function

C++ map begin() function is used to return an iterator referring to the first element of the map container.

Syntax

Parameter

None

Return value

It returns an iterator pointing to the first element of the map.

Example 1

Let's see a simple example for begin() function.

Output:

a => C++
b => Java
c => SQL

In the above, begin() function is used to return an iterator pointing to the first element in the mymap map.

Example 2

Let's see a simple example to iterate over the map using for-each loop.

Output:

Room1 = 100
Room2 = 200
Room3 = 300 

In the above example, we are using an STL algorithm std::for-each to iterate over the map. It will iterate on each of the map element and call the callback provided by us.

Example 3

Let's see a simple example to iterate over the map using while loop.

Output:

Elements are:
100: Nikita
200: Deep
300: Priya
400: Suman
500: Aman

In the above, begin() function is used to return an iterator pointing to the first element in the mymap map.

Example 4

Let's see a simple example:

Output:

Elements are:
10 + 10 = 20
20 + 20 = 40
30 + 30 = 60
The first element is: {10, 10}

In the above example, begin() function is used to return an iterator pointing to the first element in the mymap map.