## C++ Vector Size

To get the size of a C++ Vector, you can use size() function on the vector.

size() function returns the number of elements in the vector.

### Example 1: Find Vector Length using size()

In the following C++ program, we define a vector of integers, add some elements to it, and then find its length using size() function.

C++ Program

```#include <iostream>
#include <vector>
using namespace std;

int main() {
vector<int> nums;
nums.push_back(24);
nums.push_back(81);
nums.push_back(57);

cout << nums.size();
}```

Output

`3`

### Example 2: Length of Empty Vector

In the following C++ program, we define a vector of integers, with no elements in it, and then find its length using size() function. size() should return a value of zero.

C++ Program

```#include <iostream>
#include <vector>
using namespace std;

int main() {
vector<int> nums;
cout << nums.size();
}```

Output

`0`

### Example 3: Length of Vector using Foreach

You can also use C++ Foreach statement to get the length of size of a vector.

In the following program, we shall define a vector and initialize with elements. Then take a len variable with zero initial value that acts as a counter to count the number of elements in the vector. Use Foreach statement to iterate over the elements of vector and increment the counter during each iteration.

C++ Program

```#include <iostream>
#include <vector>
using namespace std;

int main() {
vector<int> nums;
nums.push_back(24);
nums.push_back(81);
nums.push_back(57);

int len = 0;
for (int element: nums)
len++;

cout << len;
}```

Output

`3`

### Conclusion

In this C++ Tutorial, we learned to find the size of vector, which is the number of elements in a vector using builtin functions or statements like foreach.