If the heap memory location starts at 9403, what is the value of the integer variable myAge at position 1? #include using namespace std; int a = 10; int main() { int b; int* myAge = nullptr; b = 20; myAge = new int; // Position 1 *myAge = 30; delete myAge; return 0; }

Question

If the heap memory location starts at 9403, what is the value of the integer variable myAge at position 1?

#include <iostream>
using namespace std;
int a = 10; 
int main() {
   int b;
   int* myAge = nullptr;
   b = 20;
   myAge = new int;    //  Position 1
   *myAge = 30;
   delete myAge;
   return 0;      
}

BlackTom AI · Accepted Answer

We start by restating the situation given in the question. The code allocates a single int on the heap with myAge = new int;, and this allocation is described as Position 1. The question then asks for the value of the integer at that position, given that the heap memory location starts at 9403.

Step 1: Understand what Position 1 refers to. The comment //  Position 1 next to the allocation suggests that Position 1 is the first (and only) dynamic int allocated on the heap. The memory address of that first heap cell, if the heap starts at 9403, would be 9403.

Step 2: Distinguish between address and value. The phrase "value of the integer variable myAge at position 1" can be interpreted in two ways:
- The value stored in the allocated int, i.e., the content at that memory location.
- The memory address of the first heap cell (the location itself).

Step 3: Follow the code flow for the value scenario. The code performs *myAge = 30; which writes the integer value 30 into the allocated memory. If you read the value at that moment (before delete), you would obtain 30. However, immediately after, the code calls delete myAge; which frees that memory. Reading from a freed (deallocated) memory location constitutes undefined behavior in C++; the program may crash, return a garbage value, or appear to work unpredictably.

Step 4: Consider the address scenario. If the question is asking for the address of the first heap cell (the position), then since the heap starts at 9403, the address of Position 1 would indeed be 9403. This aligns with an interpretation that asks for the location rather than the stored content.

Step 5: Reconciling with the provided answer. The given correct answer is 9403. This indicates the question likely aims to test understanding of memory layout (i.e., the address of the first heap allocation) rather than the stored integer value, or it treats Position 1 as the memory location rather than the runtime value stored there.

Step 6: Important caveats about the value interpretation. If someone interprets the question as asking for the stored integer value after the line *myAge = 30;, the answer would be 30 at that moment. If they then consider the memory after delete myAge;, accessing it would be undefined behavior, so no reliable value can be specified.

Step 7: Summary of reasoning for the given answer. Because the question specifies that the heap memory location starts at 9403 and labels Position 1 at the dynamic allocation, answering with 9403 corresponds to identifying the memory address of the first heap cell rather than the stored integer value. This interpretation is consistent with the address-centric reading implied by the stated starting address.

Step 8: Final reflection on misconceptions. A common pitfall is to confuse the address of a dynamically allocated object with the value stored in it. The code shows an explicit assignment of 30 to the allocated int, which would be the observable value if the object were still valid and read before deletion. However, after delete myAge; the memory is released and reading from it becomes undefined, so relying on that value is unsafe. Additionally, without explicit answer options, the question’s phrasing makes it ambiguous whether it seeks an address or a value, and the supplied answer 9403 indicates an emphasis on the address at Position 1 rather than the content stored there.

CIS-278-HYA-CRN40355 Test 2 ( In-class) Friday April 19 : 3:15-5:15 pm

If the heap memory location starts at 9403, what is the value of the integer variable myAge at position 1? #include <iostream> using namespace std; int a = 10; int main() { int b; int* myAge = nullptr; b = 20; myAge = new int; // Position 1 *myAge = 30; delete myAge; return 0; }

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