How to find how many elements are entered in an array

help
1

how to find out the number of elements user entered in an array of size 100 for example?

2

Use counter to keep track of the elements you have processed till now.
In the last print the counter.

3
  1. Using STL
vector<int> arr;
for(int i = 0,a; i < n; ++i){
     scanf("%d",&a);
     arr.emplace_back(a);
     printf("ELEMENTS ENTERED: %d\n",(int)arr.size());
}
  1. Using another variable
int arr[100], included = 0;
for(int i = 0; i < n; ++i,++included){
     scanf("%d",arr+indcluded);
     printf("ELEMENTS ENTERED: %d\n",included);
}