Predict the output

#include <iostream>
#include <vector>
using namespace std;
int main(){
  vector<int> a = {3, 1, 4, 1, 5};
  int m = a[0];
  for (int x : a) if (x > m) m = x;
  cout << m << endl;
  return 0;
}

a = [1, 1, 2, 2, 3]
w = 0
for r in range(1, len(a)):
    if a[r] != a[w]:
        w += 1
        a[w] = a[r]
print(w + 1)

const a = [0, 1, 0, 3, 12];
let w = 0;
for (let r = 0; r < a.length; r++) {
  if (a[r] !== 0) {
    [a[w], a[r]] = [a[r], a[w]];
    w++;
  }
}
console.log(a.join(' '));

#include <iostream>
#include <vector>
using namespace std;
int main(){
  vector<int> a = {1, 2, 3, 4, 5};
  int first = a[0];
  for (size_t i = 0; i + 1 < a.size(); i++) a[i] = a[i+1];
  a[a.size()-1] = first;
  for (int x : a) cout << x << ' ';
  cout << endl;
  return 0;
}

a = [5, 5, 4, 4, 3]
largest = float('-inf')
second  = float('-inf')
for x in a:
    if x > largest:
        second = largest
        largest = x
    elif x < largest and x > second:
        second = x
print(second)