What is the output of the following snippet? #include <iostream> #include <string> using namespace std; int main() { string s1[]= {"A","Z"}; string s=""; for (int i=0; i<2; i++) cout << s.append(s1[i]).insert(1,"_"); return( 0 ); } A_A__Z A__Z A_A_Z A_A

The output of the given C++ code snippet is A_A_Z.

Here's how it works:

1. The string array s1 is initialized with two elements: "A" and "Z".
2. An empty string s is initialized.
3. A for loop is set up to iterate over the elements of s1.
4. In each iteration, the append function is used to add the current element of s1 to s.
5. The insert function is then used to insert an underscore at the 1st index of the newly appended string.
6. This new string is outputted using cout.
7. In the first iteration, "A" is appended to s and an underscore is inserted at the 1st index, resulting in "A_".
8. In the second iteration, "Z" is appended to s and an underscore is inserted at the 1st index, resulting in "A_A_Z".
9. Therefore, the final output is "A_A_Z".