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Exercises

Exercises - exercises to go with the labs and lectures

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Examples

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Intro and C Basics
1_hello_world.c	Welcome to C!
1_cant_add_strings.c	You're not in Java-land anymore.
Animation of `1_cant_add_strings`	Step through with "Next >". Watch `str = str + x` especially.
1_variable_weirdness.c	"Fun" things can happen when you don't initialize variables.
1_printf.c	Printing things out with C's version of `System.out.println`.
1_fgets.c	Getting input with `fgets`... kinda.
Functions
2_get_line_fail.c	Coming up with the signature for a function that takes an array parameter.
2_get_line_success.c	The proper way to write the `get_line` function.
2_get_line_prototype.c	Using a function prototype to access a function before it's defined.
2_return_array_fail.c	Returning local arrays is a bad idea.
Pointers
3_sizeof.c	`sizeof()` might not work how you expect.
3_pointers.c	Shows the address-of `&x` and value-at `*p` operators to create and access pointers.
3_arrays_are_pointers.c	Yep. Shows array address calculation.
3_array_of_strings.c	Double-pointers are usually used for arrays-of-arrays. Like arrays of strings!
3_2d_arrays.c	2D arrays and arrays-of-arrays are actually different things!
6_const_ptrs.c	The `const` keyword is a neat addition to pointers.
6_ptr_casts.c	Pointer casting lets you "reinterpret" the meaning of bit patterns.
Animation of 6_ptr_casts	(Click "Visualize Execution") You can step through it line-by-line and see what's happening.
6_ars.c	Shows addresses of local variables inside ARs as functions are called.
Strings
4_strings_are_bad.c	Strings in C are bad, okay?
4_cant_modify_literals.c	String literals are different beasts.
4_str_size_length.c	`strlen()` and `sizeof()` are very different things.
proj4_tokenization.c	How to properly tokenize a string for the shell project.
Files
4_read_write_text_file.c	Reading/writing text files is pretty straightforward.
5_binary_file.c	Reading/writing binary files is also pretty straightforward.
The heap (malloc/free)
Linked list	(Click "Visualize Execution") Very basic linked list on the heap.
7_memory_leak.c	Use `valgrind` to see the memory this program leaks.
Use-after-free	(Click "Visualize Execution") after freeing heap memory, it's invalid.
Structs, Enums, Typedefs
5_food_struct.c	How to define and use a simple struct.
5_linked_list.c	Making self-referential struct pointers.
5_enum_color.c	Common patterns for using enums.
Misc
5_cmd_args.c	Command-line arguments, like you'll need for proj1!
10_a_terrible_function.java	Here's exactly how NOT to write a function. Thanks, MARS.
10_a_better_function.java	Pseudocode improvement of the previous function.
10_whats_wrong.c	A program that crashes. Use the debugger to figure out why!
15_asm_test.c	Stuff to look at in gdb.
Multi-file compilation and `make`
compile.sh	A very simple compilation script. You'll have to `chmod +x` it to use it.
Makefile	The makefile for the following example. IMPORTANT: make sure its name is `Makefile` exactly.
11_main.c	The main file.
11_user.c	The second file.
11_user.h	The header file for `11_user.c`.
Function Pointers
13_qsort.c	Using `qsort`.
13_qsort_structs.c	Another `qsort` example, but sorting structs this time.
ArraySorting.java	That same example, done with equivalent Java features.
13_method.c	Function pointers make Java-style method calls work.
Linking and Loading
12_main_island.c	Goes with the next file.
12_sub_island.c	Goes with the previous file.
13_innocent.c	Goes with the next file.
13_bad.c	Goes with the previous file.
Processes
14_pmap.c	Prints its own (virtual) memory map.
14_mmap.c	Uses `mmap()` to allocate some memory and to "load" a file.
17_fork.c	Demonstrates the `fork()` POSIX API function.
17_exec.c	Demonstrates the `execvp()` POSIX API function.
17_waitpid.c	Seeing how a child process terminated.
17_signal.c	Setting up a signal handler for... nefarious purposes...
Threads
21_thread_test.c	Makes 5 threads. But without joining, they do weird stuff...
ThreadTest.java	The above example implemented in Java. No weirdness if you don't join.
21_thread_switching.c	Shows how 2 threads alternate in time, but in an arbitrary way.
22_strtok.c	Multiple threads + one global variable = sadness.
22_strtok_r.c	Multiple threads + reentrant strtok = happiness.
22_thread_racing.c	A classic race condition where 2 threads try to change 1 variable.
ThreadRacing.java	The above example implemented in Java. Same problem.
22_thread_cooperating.c	The fixed version of the previous example.
ThreadCooperating.java	The above example implemented in Java. Shows `synchronized`.
22_bad_critsec.c	Another version of the previous, but with a worse design.
23_spinwait.c	If one thread has to wait for another, "spin-waiting" is not the best way.
23_condvar.c	Condition variables are a better way for threads to say "hey, wake up!"
23_barrier.c	A producer-consumer example using condition variables.
23_prodcons.c	A producer-consumer example using condition variables.