Memory management basics in Intro to Computing - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Memory Allocation

Which of the following best describes dynamic memory allocation in a computer program?

A Memory is only used to store program instructions, not data.

B Memory is fixed and reserved before the program starts running and cannot change during execution.

C Memory is allocated during program execution as needed, and can be freed when no longer required.

D Memory allocation happens only when the computer is turned off.

💡 Hint

Think about when the program decides how much memory it needs while running.

Dynamic memory allocation means the program asks the computer for memory while it is running, allowing flexible use of memory.

❓ trace

intermediate

Tracing Memory Usage in a Program

Consider this simple program that creates and deletes objects. What is the total number of objects in memory after the program finishes?

Intro to Computing

objects = []
for i in range(3):
    obj = {'id': i}
    objects.append(obj)
objects.pop(1)
objects.append({'id': 3})

A 1

B 4

C 2

D 3

💡 Hint

Count how many objects are added and removed step by step.

The program adds 3 objects, removes one, then adds one more, so total objects in the list are 3.

❓ identification

advanced

Identifying Memory Leak Causes

Which of the following scenarios is most likely to cause a memory leak in a program?

A A program keeps references to unused objects, preventing the memory from being freed.

B A program runs without any loops.

C A program uses only static memory allocation.

D A program frees memory immediately after using it.

💡 Hint

Think about what happens if memory is not released properly.

Memory leaks happen when programs hold onto memory they no longer need, preventing the system from reclaiming it.

❓ Comparison

advanced

Comparing Stack and Heap Memory

Which statement correctly compares stack and heap memory?

A Heap memory is faster and smaller than stack memory.

B Stack memory is for static, short-lived data; heap memory is for dynamic, long-lived data allocated at runtime.

C Stack memory is used for storing files; heap memory stores program instructions.

D Heap memory is automatically cleaned up; stack memory requires manual management.

💡 Hint

Think about where local variables and dynamically created objects are stored.

Stack stores local variables with fixed size and lifetime; heap stores objects created dynamically during program execution.

🔍 Analysis

expert

Output of Memory Reference Counting

What is the output of this Python code that demonstrates reference counting?

Intro to Computing

import sys

x = [1, 2, 3]
y = x
z = y
print(sys.getrefcount(x))

A 4

B 3

C 1

D 0

💡 Hint

Remember that getrefcount includes the temporary reference as an argument.

The list x has references from x, y, z, and the argument passed to getrefcount, totaling 4.