C++ set count()

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

Syntax

Parameter

val: Value to be searched in the set container.

Return value

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

Complexity

Logarithmic in size.

Iterator validity

No changes.

Data Races

The container is accessed.

Concurrently accessing the elements of a set is safe.

Exception Safety

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

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 set 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 set:

Output:

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

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

Example 3

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

Output:

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

In the above example, key 'a' is present in the set m so, it will be the value of 'a' and key 'z' is not present in the set so, 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.