What will be the output of the following program?#include using namespace std; int main() { int arr[] = {5, 10, 15, 20}; for (auto elem : arr) { elem += 5; } for (auto elem : arr) { cout

Question

What will be the output of the following program?#include <iostream> using namespace std; int main() {
int arr[] = {5, 10, 15, 20}; for (auto elem : arr) {
elem += 5; }
for (auto elem : arr) {
cout << elem << " "; }
return 0; }

BlackTom AI · Accepted Answer

The question presents a C++ program and asks for its output. There are no explicit answer options provided in the option list, but the given answer field mentions 'b. 5 10 15 20'.

First, consider what the code does. The array arr is initialized as {5, 10, 15, 20}. The first range-based for loop uses 'for (auto elem : arr)' which copies each element into the variable elem. Inside the loop, the statement 'elem += 5;' increases the local copy by 5, but does not modify the original array because 'elem' is a separate copy, not a reference to the array element.

Because no assignment back to the array occurs, the elements of arr remain unchanged after the first loop. In the second range-based for loop, 'for (auto elem : arr)', again elem is a copy of each array element, and we print 'elem' followed by a space. Since arr is still {5, 10, 15, 20}, the output will be '5 10 15 20' with a trailing space.

Now addressing the stated options: since the options are not provided in the list, we can still evaluate the result against the described option 'b. 5 10 15 20'. The observed output matches this sequence exactly, given the lack of modifications to the original array.

Key takeaway: range-based for loops with 'auto' create copies of elements by default; modifying the loop variable does not alter the underlying array unless the loop variable is a reference (e.g., 'for (auto& elem : arr)' or 'for (int& elem : arr)'). In this code, because copies are used, the array remains unchanged and prints its original values.

What will be the output of the following program?#include <iostream> using namespace std; int main() { int arr[] = {5, 10, 15, 20}; for (auto elem : arr) { elem += 5; } for (auto elem : arr) { cout << elem << " "; } return 0; }单项选择题

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