The **`stack.size()`** function in C++ returns the number of elements in the stack. In other words, this function is used to get the current size of the stack. 

The following illustration shows the visual representation of the `stack.size()` function.

In order to use the `stack.size()` function, you must include `stack` in the program, as shown below:

```c++
#include <stack>
```
#     
## Syntax
```c++
stack_name.size()
// where the stack_name is the name of the stack
```
## Parameters
This function does not require a parameter.

## Return value
The `stack.size()` function returns the number of elements in the stack. 

## Code


#include <iostream>
//header file
#include <stack>
using namespace std;

int main() {
  //filled stack
  stack<int> stack1;
    stack1.push(0);
    stack1.push(2);
    stack1.push(5);
    stack1.push(3);
    stack1.push(1);
    //stack1 = 1->3->5->2->0
    cout<<"The length of stack1: \n"<<stack1.size()<<"\n"; 

  //empty stack  
  stack<int> stack2;
    cout<<"The length of stack2: \n"<<stack2.size(); 
}

What is stack.size() in C++?

Syntax

Parameters

Return value

Code