Computer Science Basics Quiz

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Questions and Answers

What is the main purpose of the malloc function in C?

To allocate a specified number of bytes in the heap (correct)

To free previously allocated memory

To automatically manage memory allocation

To define the size of arrays at compile time

Which statement about memory management in C is true?

malloc returns a pointer that must always be of type int.

Heap memory must be freed after use to avoid memory leaks. (correct)

Arrays in C can dynamically change their size during execution.

The stack can allocate an unlimited amount of memory.

How can we allocate memory for 10,000 integers using malloc?

malloc(sizeof(int) * 1000);

malloc(10000 * sizeof(int)); (correct)

malloc(10 * sizeof(int));

malloc(10000);

What type of pointer does malloc return?

Void pointer Signup and view all the answers

What is the result of not freeing heap memory after its use?

It can lead to memory leaks in the program. Signup and view all the answers

What notation is used to access values in a C array?

Both B and C Signup and view all the answers

Why do we not need the address-of operator when using scanf for strings in C?

Strings are treated as pointers. Signup and view all the answers

Which statement about arrays in C is true?

An array is a contiguous block of memory. Signup and view all the answers

What is the primary function of the Arithmetic Logic Unit (ALU) within the CPU?

To perform calculations on data Signup and view all the answers

What is true about the way arrays are passed to functions?

They are passed by reference, allowing modifications. Signup and view all the answers

Which of the following statements is correct regarding pointers?

Pointers store the address of another variable. Signup and view all the answers

What key piece of information is often necessary to pass along with an array to a function?

The size of the array Signup and view all the answers

In which way should a pointer variable be declared?

With a space between the type and the pointer name Signup and view all the answers

Which is a correct behavior of memory allocation in programming?

Memory allocation occurs automatically for all variables. Signup and view all the answers

When declaring multiple pointers in one line, what must be ensured?

All pointers must point to the same data type. Signup and view all the answers

How are control signals utilized within the CPU?

To guide execution of instructions Signup and view all the answers

Study Notes

CPU Components

The Arithmetic Logic Unit (ALU) performs calculations
The control unit manages the execution of instructions
Registers are high-speed memory used by the CPU during calculations
Memory stores program data and instructions

Passing Arrays to Functions

Arrays are passed by reference, meaning functions can modify the array's contents
When passing arrays, it's often necessary to also pass the array's length for correct function operation

String Methods

Strings in C are stored as arrays of characters
There are built-in functions for manipulating strings, such as strlen, strcpy, and strcmp

Pointers

A pointer variable stores the memory address of another variable
Pointers are declared using the asterisk (*)
Pointers must be assigned the correct data type
To assign the address of a variable to a pointer, use the address-of operator (&)

Memory Allocation

Memory is automatically managed by the compiler on the stack
The heap allows manual allocation of memory using malloc
Malloc takes the number of bytes to allocate as an argument
Once memory is no longer needed, it should be freed using the free function to avoid memory leaks

Arrays are Pointers

In C, arrays are essentially pointers to blocks of memory
Array notation (using square brackets) and pointer offset notation are equivalent ways to access elements
Strings in C are arrays, which explains why scanf doesn't need the address-of operator for string input

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Description

Test your knowledge on essential computer science concepts including CPU components, passing arrays to functions, string methods, pointers, and memory allocation. This quiz covers crucial programming fundamentals to help solidify your understanding.