C++ multiset count()

C++ Multiset count() function is used to return the number of elements found in the container. Since, the multiset container does not contain any duplicate element, this function actually returns 1 if the element with value val is present in the multiset container otherwise, it returns 0.

Syntax

Parameter

val: Value to be searched in the multiset container.

Return value

It returns 1 if the element with value val is present in the multiset container or 0 otherwise.

Complexity

Logarithmic in size.

Iterator validity

No changes.

Data Races

The container is accessed.

Concurrently accessing the elements of container is safe.

Exception Safety

If an exception is thrown, there are no changes in the multiset.

Example 1

Let's see the simple example to search the element with the given key value:

Output:

The key 30 is present
The key 100 is not present

In the above example, count() function checks for the given value. If the element is present in the multiset container, then it will display the message that element is present otherwise, not present.

Example 2

Let's see a simple example to search for the elements of the multiset:

Output:

a is an element of mymultiset.
b is not an element of mymultiset.
c is an element of mymultiset.
d is not an element of mymultiset.
e is not an element of mymultiset.
f is an element of mymultiset.
g is not an element of mymultiset.

In the above example, count() function is used to search for the 'a' to 'h' elements in the multiset.

Example 3

Let's see a simple example to search keys in the multiset:

Output:

'a' is present in the multiset 
'z' is not present in the multiset

In the above example, key 'a' is present in the multiset m hence, it will be the value of 'a' and key 'z' is not present in the multiset hence, there is no value of 'z'.

Example 4

Let's see a simple example:

Output:

The number of elements in s1 with a sort key of 1 is: 1.
The number of elements in s1 with a sort key of 2 is: 0.